If y = (x + 3)2, then (-2x - 6)2 must equal which of the following?

A.
-4y2

B.
-2y2

C. -4y
D. 4y

wHAT FORMULA DO I USE TO GET THE ANSWER?

Question

If y = (x + 3)2, then (-2x - 6)2 must equal which of the following?

A.
-4y2

B.
-2y2

C. -4y 	
  D. 4y

wHAT FORMULA DO I USE TO GET THE ANSWER?

anonymous · Answer

Does anyone know what formula I use to get the answer?

anonymous · Answer

You use math...

$$y = (x+3)^2$$
$$\sqrt(y) = x+3$$
$$(-2x-6)^2 = (-2\sqrt(y))^2$$
=4y

(...gotta learn how to write latex again)

anonymous · Answer

@nphuongsun93  Thank can you walk me through the steps so I know how to do it with other problems?

anonymous · Answer

Ok. 
$$y = (x+3)^2$$$$\sqrt(y) = x+3$$ Understand this so far?

jdoe0001 · Answer

hint:   $ y={\color{brown}{ (x+3)^2 }}\qquad (-2x-6)^2\to 
\begin{cases}
[-2(x+3)]^2\impliedby \textit{common factor}\
(-2)^2(x+3)^2\impliedby expanded\
+4{\color{brown}{ (x+3)^2 }}
\end{cases}$