Multiply mentally
-$(-7+3 x)(7+3 x)$
A) $9 x^{2}+42 x-49$
B) $9 x^{2}-42 x-49$
C) $x^{2}-49$
D) $9 x^{2}-49$

Name: Multiply mentally -$(-7+3 x)(7+3 x)$ A) $9 x^{2}+42 x-49$ B) $9 x^{2}-42 x-49$ C) $x^{2}-49$ D) $9 x^{2}-49$
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Question

Quizplus · Accepted Answer

This is a difference of squares problem, which follows the formula $a^2 - b^2 = (a+b)(a-b)$. Here, $a = 3x$ and $b = 7$, so $a^2 = (3x)^2 = 9x^2$ and $b^2 = 7^2 = 49$. Thus, the product is $9x^2 - 49$.

Multiply Mentally - (−7+3x)(7+3x)(-7+3 x)(7+3 x)(−7+3x)(7+3x) A) 9x2+42x−499 x^{2}+42 x-499x2+42x−49 B) 9x2−42x−499 x^{2}-42 x-499x2−42x−49

Multiply Mentally
- $(-7+3 x)(7+3 x)$ A) $9 x^{2}+42 x-49$ B) $9 x^{2}-42 x-49$