Question

Z=15+2(x+y) solve for x

Answer 1

Z=15+2(x+y) 
Use distributive property
Z= 15 + 2x + 2y
Subtract 2y from both sides
Z - 2y= 15 + 2x
Subtract 15 from both sides
Z - 2y - 15= 2x
Divide 2 on both sides
Final Answer: Z - 2y - 15(All over 2)= x

Answer 2

Z=15+2x+2y
0=15+2x+2y-15
-2x=15+2y-15
$x= -\frac{15}{2} - y + \frac{15}{2}$