EDGE Math 8

Choose the correct factored form of each polynomial.

1.	$9 a^{4} - b^{4}$

(3 a^{2} - b^{2}) (3 a^{2} + b^{2})

(3 a^{2} + b^{2}) (a + b) (a - b)

{(3 a^{2} - b^{2})}^{2}

none of the choices

Answer: $(3 a^{2} - b^{2}) (3 a^{2} + b^{2})$

2.	$3 x^{3} - 12 x$

3 x {(x - 2)}^{2}

3 x (x^{2} - 4)

3 x (x + 2) (x - 2)

none of the choices

Answer: $3 x (x + 2) (x - 2)$

3.	$x^{3} + x^{2} - x - 1$

{(x - 1)}^{2} (x + 1)

{(x + 1)}^{2} (x - 1)

{(x - 1)}^{3}

none of the choices

Answer: ${(x + 1)}^{2} (x - 1)$

4.	$4 a b^{3} - a^{3} b$

a b {(2 b - a)}^{2}

a b (2 b - a) (2 b + a)

a b {(2 b + a)}^{2}

none of the choices

Answer: $a b (2 b - a) (2 b + a)$

5.	$2 a c + a d + 2 b c + b d$

(2 c + a) (d + b)

(2 a + d) (c + b)

(2 c + b) (a + d)

none of the choices

Answer: none of the choices; the answer is $(2 c + d) (a + b)$

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