Factor the expression $( x + 4 y ) ^ { 2 } - 9 a ^ { 2 }$ completely.
A) $( x + 4 y + 3 a ) ( x - 4 y - 3 a )$
B) $( x + 4 y - 3 a ) ^ { 2 }$
C) $( x + 4 y + 3 a ) ^ { 2 }$
D) $( x + 4 y + 9 a ) ( x + 4 y - 9 a )$
E) $( x + 4 y + 3 a ) ( x + 4 y - 3 a )$

Question

Quizplus · Accepted Answer

We can use the difference of squares formula to factor the expression as
$$(x+4y+3a)(x+4y-3a)-(9a^2)=(x+4y+3a)(x+4y-3a-9a)+(3a)(-9a)$$
$$=(x+4y+3a)(x+4y-12a)$$
Therefore, the answer is E.

Factor the Expression (x+4y)2−9a2( x + 4 y ) ^ { 2 } - 9 a ^ { 2 }(x+4y)2−9a2

Factor the Expression $( x + 4 y ) ^ { 2 } - 9 a ^ { 2 }$