If you were to use the substitution method to solve the following system, choose the new equation after the expression equivalent to x from the second equation is substituted into the first equation.

2x – 3y = –29
x + 4y = 13 (5 points)

2(4y + 13) – 3y = –29
2(–4y + 13) – 3y = –29
2x – 3(4y + 13) = –29
2x – 3(–4y + 13) = –29

Question

If you were to use the substitution method to solve the following system, choose the new equation after the expression equivalent to x from the second equation is substituted into the first equation.

2x – 3y = –29
x + 4y = 13 (5 points)

 	
	2(4y + 13) – 3y = –29
	2(–4y + 13) – 3y = –29
	2x – 3(4y + 13) = –29
	2x – 3(–4y + 13) = –29

anonymous · Answer

So first, we need to solve for $x$ in the second equation.

anonymous · Answer

$$
\underbrace{x + 4y}_{-4y} = \underbrace{13}_{-4y}\
x =  13-4y
$$

jdoe0001 · Answer

x + 4y = 13    <---- solve for "x" first, as wio pointed out

vera_ewing · Answer

do we divide by 4 on both sides now?

anonymous · Answer

No, the $x$ is isolated so it is good.

vera_ewing · Answer

so now what? what would the answer be? i think it's B

anonymous · Answer

You substitute right side into $x$.

The answer is B