Question

What is 3x-7y=z for x

Answer 1

We want to find x in times of y and z, so we want to have only 1 x on the LHS of equation, so
3x-7y=z      /+7z   (add 7z both sides)
3x=z+7z      /:3 (divide 3 both sides)
$x= \frac{z+7y}{3}$ - its the result.

Answer 2

X=7/3y+1/3z , answer