Question

SEE ATTACHED IMAGE

1) 12x^3+8x
2) 18a^2+2a
3) 25b^4+30b^3

1. Factor each term and mark the common factors.
2. Multiply the common factors to find the GCF.
3. Rewrite each term as the product of the GCF and other factors.
4. Rewrite the expression using the factors from the previous step.
5. Use the distributive property: ab ac + = a b( ) +c .

Answer 1

Explanation:

remember the GCF (greatest common factor) ?

every number or term is the product of certain prime numbers (prime factors).

the product of factors that the discussed numbers or terms have in common is the GCF.

1)

12x³ + 8x

12x³ :

12 / 2 = 6

6 / 2 = 3

3 / 2 no

3 / 3 = 1 finished

12 = 2×2×3

x³ = x×x×x

so,

12x³ = 2×2×3×x×x×x

8x :

8 / 2 = 4

4 / 2 = 2

2 / 2 = 1 finished

8 = 2×2×2

x = x

so,

8x = 2×2×2×x

what factors do they have in common ?

2×2×x = 4x

so, the GCF = 4x

that means

12x³ + 8x = 4x×3x² + 4x×2 = 4x(3x² + 2)

2)

18a² + 2a

18a² :

18 / 2 = 9

9 / 2 no

9 / 3 = 3

3 / 3 = 1 finished

18a² = 2×3×3×a×a

2a :

2 / 2 = 1 finished

2a = 2×a

so, they have 2×a = 2a in common.

the GCF = 2a.

that means

18a² + 2a = 2a×9a + 2a×1 = 2a(9a + 1)

3)

25b⁴ + 30b³

25b⁴ :

25 / 2 no

25 / 3 no

25 / 5 = 5

5 / 5 = 1 finished

25b⁴ = 5×5×b×b×b×b

30b³ :

30 / 2 = 15

15 / 2 no

15 / 3 = 5

5 / 3 no

5 / 5 = 1 finished

30b³ = 2×3×5×b×b×b

so, they have 5×b×b×b = 5b³ in common.

the GCF = 5b³

that means

25b⁴ + 30b³ = 5b³×5b + 5b³×6 = 5b³(5b + 6)