February 10, 2010

Algebra: Factoring of Polynomials

For convenience and quick browsing, the problems are grouped into polynomials that are:
  • product of a monomial and a polynomial
  • grouped into terms containing a common factor
  • difference of two squares
  • difference of two cubes
  • sum of two cubes
  • product of two binomials
The last group of polynomials given above consists of polynomials that are:
  • product of two binomials having a common factor
  • product of any two binomials
  • square of a binomial sum
  • square of a binomial difference
Some of these grouped polynomials contain factors which are a combination of a monomial, a binomial, and a trinomial. Polynomials that are:
  • difference of two squares can be the products of two binomials, or products of two trinomials, or products of a monomial and two binomials.
  • sum of two cubes can be products of a binomial and a trinomial, or products of a monomial, a binomial, and a trinomial

Polynomials With Monomial As One of Its Factors

1.15x4 + 15x3y
Answer: (3x3)(5x + 5y)
2.4x3 - 4x2y4
Answer: (4x2)(x - y4)
3.5x5 - 5x3y2
Answer: (x3)(5x2 - 5y2)
4.63s6t3 - 42s3t3u + 126s3t3
Answer: (21s3t3)(3s3 - 2u + 6)
5.14x5 + 6x2y
Answer: (2x2)(7x3 + 3y)
6.18x6y3 - 15x2y3z2 + 3x2y3
Answer: (3x2y3)(6x4 - 5z2 + 1)
7.14a4b4 + 56a3b4
Answer: (14a3b4)(a + 4)
8.7x5 + xy2
Answer: (x)(7x4 + y2)
9.7x4 + 21x3y3
Answer: (7x3)(x + 3y3)
10.24x6y4 - 192x3y4
Answer: (24x3y4)(x3 - 8)
11.35x3 - 49xy2
Answer: (7x)(5x2 - 7y2)
12.48a4b2 + 12a3b2
Answer: (12a3b2)(4a + 1)
13.56x4 - 40xy4
Answer: (8x)(7x3 - 5y4)
14.20a3b2 + 60ab2
Answer: (20ab2)(a2 + 3)
15.120s5t3 - 75s2t3u2 + 30s2t3
Answer: (15s2t3)(8s3 - 5u2 + 2)
16.24x4y - 6x3y
Answer: (6x3y)(4x - 1)
17.105x5y - 35x3y
Answer: (35x3y)(3x2 - 1)
18.30x5 - 15x2y3
Answer: (5x2)(6x3 - 3y3)
19.6x4 + 8x3y4
Answer: (x3)(6x + 8y4)
20.20x4y3 - 40xy3
Answer: (20xy3)(x3 - 2)

Polynomials That Can Be Grouped Into Terms Having A Common Factor

1.su4 + sv + tu4 + tv
Answer: (s + t)(u4 + v)
2.wy + 3wz + xy + 3xz
Answer: (w + x)(y + 3z)
3.24su - 42sv + 20tu - 35tv
Answer: (6s + 5t)(4u - 7v)
4.20w2y4 + 35w2z4 + 8xy4 + 14xz4
Answer: (5w2 + 2x)(4y4 + 7z4)
5.64w4y3 - 40w4z2 + 8xy3 - 5xz2
Answer: (8w4 + x)(8y3 - 5z2)
6.3ab + 3a + b2 + b
Answer: (3a + b)(b + 1)
7.5xy - 20x + 2y2 - 8y
Answer: (5x + 2y)(y - 4)
8.28s3t - 35s3 + 24t2 - 30t
Answer: (7s3 + 6t)(4t - 5)
9.7su + sv - 7tu - tv
Answer: (s - t)(7u + v)
10.su3 + sv4 + tu3 + tv4
Answer: (s + t)(u3 + v4)
11.8wy + 32wz + 3xy + 12xz
Answer: (8w + 3x)(y + 4z)
12.6su - 16sv + 3tu - 8tv
Answer: (2s + t)(3u - 8v)
13.12w2y + 15w2z2 + 8x3y + 10x3z2
Answer: (3w2 + 2x3)(4y + 5z2)
14.3w3y4 - 8w3z3 + 15x4y4 - 40x4z3
Answer: (w3 + 5x4)(3y4 - 8z3)
15.4ab + 2a + 10b2 + 5b
Answer: (2a + 5b)(2b + 1)
16.28xy - 4x + 7y2 - y
Answer: (4x + y)(7y - 1)
17.24st2 - 15s + 64t4 - 40t2
Answer: (3s + 8t2)(8t2 - 5)
18.5su + 2sv - 5tu - 2tv
Answer: (s - t)(5u + 2v)
19.12ab + 42a + 14b2 + 49b
Answer: (6a + 7b)(2b + 7)
20.6xy - 10x + 9y2 - 15y
Answer: (2x + 3y)(3y - 5)

Polynomials That Are The Difference of Two Squares

You will find that some of the problems given below can be factored twice, that is, after factoring an expression one of the resulting factors is still factorable.

Also, in some problems a group of terms is treated as a single term.

1.x2 - 25
Answer: (x - 5)(x + 5)
2.36x2 - 25
Answer: (6x - 5)(6x + 5)
3.25x2 - 49
Answer: (5x - 7)(5x + 7)
4.x2 - 9
Answer: (x - 3)(x + 3)
5.16x2 - 25
Answer: (4x - 5)(4x + 5)
6.x2 - (y - z)2
Answer: [ x + (y - z) ] [ (x - (y - z) ]
7.(x + 8)2 - 9
Answer: [ (x + 8) + 3 ] [ (x + 8) - 3 ]
8.(x + 3)2 - 1
Answer: [ (x + 3) + 1 ] [ (x + 3) - 1 ]
9.49x2 - 9(y - z)2
Answer: [ 7x + 3(y - z) ] [ (7x - 3(y - z) ]
10.(x + 5)2 - 9
Answer: [ (x + 5) + 3 ] [ (x + 5) - 3 ]
11.(x + 1)2 - 36
Answer: [ (x + 1) + 6 ] [ (x + 1) - 6 ]
12.(x + 8)2 - 25
Answer: [ (x + 8) + 5 ] [ (x + 8) - 5 ]
13.16x2 - 49(y - z)2
Answer: [ 4x + 7(y - z) ] [ (4x - 7(y - z) ]
14.49x4y2 - 49x4z2
Answer: 49x4 (y + z) (y - z)
15.49x2y2 - 441x2z2
Answer: 49x2 (y + 3z) (y - 3z)
16.9x2y2 - 36x2z2
Answer: 9x2 (y + 2z) (y - 2z)
17.16x2y2 - 144x2z2
Answer: 16x2 (y + 3z) (y - 3z)
18.4x2y2 - 100x2z2
Answer: 4x2 (y + 5z) (y - 5z)
19.x4 - 256y4
Answer: (x + 4y) (x - 4y) (x2 + 16y2)
20.x4 - 81y4
Answer: (x + 3y) (x - 3y) (x2 + 9y2)

Polynomials That Are The Difference of Two Cubes

1.27x3y6 - 125z3
Answer: (3xy2 - 5z) (9x2y4 + 15xy2z + 25z2)
2.343y6 - 512
Answer: (7y2 - 8) (49y4 + 56y2 + 64)
3.8a6 - 125b3
Answer: (2a2 - 5b) (4a4 + 10a2b + 25b2)
4.x3 - 8
Answer: (x - 2) (x2 + 2x + 4)
5.8a3 - 512b3
Answer: (2a - 8b) (4a2 + 16ab + 64b2)
6.343x3y6 - 64z3
Answer: (7xy2 - 4z) (49x2y4 + 28xy2z + 16z2)
7.512y3 - 125
Answer: (8y - 5) (64y2 + 40y + 25)
8.27a6 - 125b3
Answer: (3a2 - 5b) (9a4 + 15a2b + 25b2)
9.8a3 - 125b3
Answer: (2a - 5b) (4a2 + 10ab + 25b2)
10.125y6 - 216
Answer: (5y2 - 6) (25y4 + 30y2 + 36)
11.343y3 - 216
Answer: (7y - 6) (49y2 + 42y + 36)
12.x6 - 8
Answer: (x2 - 2) (x4 + 2x2 + 4)
13.8y3 - 125
Answer: (2y - 5) (4y2 + 10y + 25)
14.8y3 - 216
Answer: (2y - 6) (4y2 + 12y + 36)
15.343y6 - 27
Answer: (7y2 - 3) (49y4 + 21y2 + 9)
16.x6 - 64
Answer: (x2 - 4) (x4 + 4x2 + 16)
17.x6 - 27
Answer: (x2 - 3) (x4 + 3x2 + 9)
18.x3 - 27
Answer: (x - 3) (x2 + 3x + 9)
19.8y6 - 343
Answer: (2y2 - 7) (4y4 + 14y2 + 49)
20.27y6 - 27
Answer: (3y2 - 3) (9y4 + 9y2 + 9)
21.512a3 - 8b3
Answer: (8a - 2b) (64a2 + 16ab + 4b2)
22.64a6 - 343b3
Answer: (4a2 - 7b) (16a4 + 28a2b + 49b2)
23.8a3 - 8b3
Answer: (2a - 2b) (4a2 + 4ab + 4b2)
24.x3 - 125
Answer: (x - 5) (x2 + 5x + 25)
25.512a6 - 8b3
Answer: (8a2 - 2b) (64a4 + 16a2b + 4b2)

Polynomials That Are The Sum of Two Cubes

1.512x6 + 27y6
Answer: (8x2 + 3y2) (64x4 - 24x2y2 + 9y4)
2.8x6 + 27y6
Answer: (2x2 + 3y2) (4x4 - 6x2y2 + 9y4)
3.8a6 + 125b6
Answer: (2a2 + 5b2) (4a4 - 10a2b2 + 25b4)
4.512x3 + 8y3
Answer: (8x + 2y) (64x2 - 16xy + 4y2)
5.8x6 + 64y6
Answer: (2x2 + 4y2) (4x4 - 8x2y2 + 16y4)
6.8m3 + 343n3
Answer: (2m + 7n) (4m2 - 14mn + 49n2)
7.64s3x + 8t3x
Answer: x (4s + 2t)(16s2 - 8st + 4t2)
8.8x3 + 216y3
Answer: (2x + 6y) (4x2 - 12xy + 36y2)
9.125x6y + 343y
Answer: y (5x2 + 7)(25x4 - 35x2 + 49)
10.125x3 + 8y3
Answer: (5x + 2y) (25x2 - 10xy + 4y2)
11.512x6 + 343y6
Answer: (8x2 + 7y2) (64x4 - 56x2y2 + 49y4)
12.8x3 + 125y3
Answer: (2x + 5y) (4x2 - 10xy + 25y2)
13.125a6x + 64b6x
Answer: x (5a2 + 4b2)(25a4 - 20a2b2 + 16b4)
14.64m3y + 27n3y
Answer: y (4m + 3n)(16m2 - 12mn + 9n2)
15.64s3x + 125t3x
Answer: x (4s + 5t)(16s2 - 20st + 25t2)
16.216x3z + 343y3z
Answer: z (6x + 7y)(36x2 - 42xy + 49y2)
17.8s6x + 125t6x
Answer: x (2s2 + 5t2)(4s4 - 10s2t2 + 25t4)
18.343a3c + 64b3c
Answer: c (7a + 4b)(49a2 - 28ab + 16b2)
19.512s6x + 343t6x
Answer: x (8s2 + 7t2)(64s4 - 56s2t2 + 49t4)
20.8s6u + 27t6u
Answer: u (2s2 + 3t2)(4s4 - 6s2t2 + 9t4)


The following problems are about polynomials which are the products of two binomials.

Polynomials That Are The Products of Two Binomials Having a Common Factor

1.x2 + 11x + 30
Answer: (x + 5)(x + 6)
2.x2 - 11x + 24
Answer: (x - 3)(x - 8)
3.x2 + 8x + 15
Answer: (x + 3)(x + 5)
4.49x2 - 35x + 4
Answer: (7x - 1)(7x - 4)
5.x2 - 9x + 14
Answer: (x - 2)(x - 7)
6.x2 + 5x + 4
Answer: (x + 1)(x + 4)
7.x2 - x - 30
Answer: (x - 6)(x + 5)
8.x2 + 7x + 10
Answer: (x + 5)(x + 2)
9.25x2 + 65x + 42
Answer: (5x + 6)(5x + 7)
10.x2 + x - 56
Answer: (x - 7)(x + 8)
11.x2 - 9x + 8
Answer: (x - 1)(x - 8)
12.x2 + 2x - 15
Answer: (x - 3)(x + 5)
13.x2 + 13x + 42
Answer: (x + 6)(x + 7)
14.x2 + 11x + 24
Answer: (x + 8)(x + 3)
15.x2 - 11x + 30
Answer: (x - 5)(x - 6)
16.x2 - 13x + 40
Answer: (x - 5)(x - 8)
17.x2 + x - 30
Answer: (x - 5)(x + 6)
18.x2 + 3x + 2
Answer: (x + 2)(x + 1)
19.x2 - 2x - 3
Answer: (x - 3)(x + 1)
20.x2 - 8x + 15
Answer: (x - 5)(x - 3)

Polynomials That Are The Products of Any Two Binomials

1.24x2 + 35x - 49
Answer: (8x - 7)(3x + 7)
2.2x2 + 7x - 4
Answer: (2x - 1)(x + 4)
3.24x2 + 34x + 7
Answer: (6x + 7)(4x + 1)
4.32x2 + 28x + 3
Answer: (8x + 1)(4x + 3)
5.33x2 + 14x + 1
Answer: (3x + 1)(11x + 1)
6.12x2 + 11x - 5
Answer: (3x - 1)(4x + 5)
7.5x2 + 33x - 56
Answer: (5x - 7)(x + 8)
8.8x2 - 9x + 1
Answer: (x - 1)(8x - 1)
9.3x2 + 19x + 6
Answer: (x + 6)(3x + 1)
10.6x2 - 25x + 14
Answer: (3x - 2)(2x - 7)
11.35x2 + 17x - 30
Answer: (7x - 5)(5x + 6)
12.7x2 + 38x + 15
Answer: (7x + 3)(x + 5)
13.3x2 + 32x + 64
Answer: (x + 8)(3x + 8)
14.3x2 - 13x + 12
Answer: (x - 3)(3x - 4)
15.10x2 + 21x + 9
Answer: (2x + 3)(5x + 3)
16.6x2 - 23x + 20
Answer: (3x - 4)(2x - 5)
17.10x2 - 47x + 42
Answer: (2x - 7)(5x - 6)
18.6x2 - 43x + 42
Answer: (6x - 7)(x - 6)
19.15x2 + 4x - 32
Answer: (3x - 4)(5x + 8)
20.3x2 - 14x - 5
Answer: (x - 5)(3x + 1)

Polynomials That Are The Square of a Binomial Sum

1.169x2 + 364x + 196
Answer: (13x + 14)(13x + 14)
2.64x2 + 80x + 25
Answer: (8x + 5)(8x + 5)
3.25x2 + 40x + 16
Answer: (5x + 4)(5x + 4)
4.x2 + 10x + 25
Answer: (x + 5)(x + 5)
5.64x2 + 48x + 9
Answer: (8x + 3)(8x + 3)
6.25x2 + 60x + 36
Answer: (5x + 6)(5x + 6)
7.16x2 + 8x + 1
Answer: (4x + 1)(4x + 1)
8.x2 + 22x + 121
Answer: (x + 11)(x + 11)
9.169x2 + 78x + 9
Answer: (13x + 3)(13x + 3)
10.x2 + 4x + 4
Answer: (x + 2)(x + 2)
11.49x2 + 56x + 16
Answer: (7x + 4)(7x + 4)
12.x2 + 2x + 1
Answer: (x + 1)(x + 1)
13.x2 + 14x + 49
Answer: (x + 7)(x + 7)
14.169x2 + 156x + 36
Answer: (13x + 6)(13x + 6)
15.x2 + 16x + 64
Answer: (x + 8)(x + 8)
16.x2 + 26x + 169
Answer: (x + 13)(x + 13)
17.64x2 + 16x + 1
Answer: (8x + 1)(8x + 1)
18.x2 + 8x + 16
Answer: (x + 4)(x + 4)
19.25x2 + 110x + 121
Answer: (5x + 11)(5x + 11)
20.49x2 + 42x + 9
Answer: (7x + 3)(7x + 3)

Polynomials That Are The Square of a Binomial Difference

1.9x2 - 30x + 25
Answer: (3x - 5)(3x - 5)
2.169x2 - 364x + 196
Answer: (13x - 14)(13x - 14)
3.25x2 - 40x + 16
Answer: (5x - 4)(5x - 4)
4.49x2 - 42x + 9
Answer: (7x - 3)(7x - 3)
5.9x2 - 60x + 100
Answer: (3x - 10)(3x - 10)
6.64x2 - 80x + 25
Answer: (8x - 5)(8x - 5)
7.36x2 - 84x + 49
Answer: (6x - 7)(6x - 7)
8.x2 - 26x + 169
Answer: (x - 13)(x - 13)
9.9x2 - 12x + 4
Answer: (3x - 2)(3x - 2)
10.x2 - 2x + 1
Answer: (x - 1)(x - 1)
11.x2 - 14x + 49
Answer: (x - 7)(x - 7)
12.x2 - 4x + 4
Answer: (x - 2)(x - 2)
13.4x2 - 20x + 25
Answer: (2x - 5)(2x - 5)
14.x2 - 8x + 16
Answer: (x - 4)(x - 4)
15.25x2 - 80x + 64
Answer: (5x - 8)(5x - 8)
16.x2 - 16x + 64
Answer: (x - 8)(x - 8)
17.x2 - 6x + 9
Answer: (x - 3)(x - 3)
18.64x2 - 16x + 1
Answer: (8x - 1)(8x - 1)
19.x2 - 10x + 25
Answer: (x - 5)(x - 5)
20.49x2 - 70x + 25
Answer: (7x - 5)(7x - 5)