Factor completely.
-$$175 x ^ { 2 } - 28 y ^ { 2 }$$
A) $7 ( 5 x + 2 y ) ( 5 x - 2 y )$
B) $7 ( 5 x - 2 y ) ^ { 2 }$
C) $( 5 x + 2 y ) ( 35 x - 14 y )$
D) $( 35 x + 14 y ) ( 5 x - 2 y )$

Question

Quizplus · Accepted Answer

We can factor out the greatest common factor of 7 and then use the difference of squares.
\begin{align*}
175 x ^ { 2 } - 28 y ^ { 2 } &= 7 \cdot 25x^2 - 7\cdot 4y^2\
&=7(25x^2-4y^2)\
&=7(5x+2y)(5x-2y)
\end{align*} 
Thus, the correct choice is (A).

Factor Completely 175x2−28y2175 x ^ { 2 } - 28 y ^ { 2 }175x2−28y2

Factor Completely $175 x ^ { 2 } - 28 y ^ { 2 }$