Question

Solve for x.y=7x−7z−9 Answer choices:x=(y−z−9)/7x=(y+7z+9)/7x=(y−7z−9)/7x=(y+z+9)/7

Answer 1

We have the following equation:

$y=7x-7z-9$

and we need to solve it for x. Then, by moving -7z and -9 to the left hand side, we have

$\begin{gathered} y+7z+9=7x \\ or\text{ equivalently} \\ 7x=y+7z+9 \end{gathered}$

Now, by moving the coefficient of x to the right hand side,we get

$x=\frac{y+7z+9}{7}$

therefore, the answer is option 2.