[tex]Simplifying
x + -8y = 40
Solving
x + -8y = 40
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '8y' to each side of the equation.
x + -8y + 8y = 40 + 8y
Combine like terms: -8y + 8y = 0
x + 0 = 40 + 8y
x = 40 + 8y
Simplifying
x = 40 + 8y[/tex]