My 14 yr old son tells me:
y=7-2x
Since x is on the right-hand side of the equation, switch the sides so it is on the left-hand side of the equation.
7-2x=y
Since 7 does not contain the variable to solve for, move it to the right-hand side of the equation by subtracting 7 from both sides.
-2x=-7+y
Move all terms not containing x to the right-hand side of the equation.
-2x=y-7
Divide each term in the equation by -2.
-(2x)/(-2)=(y)/(-2)-(7)/(-2)
Simplify the left-hand side of the equation by canceling the common factors.
x=(y)/(-2)-(7)/(-2)
Simplify the right-hand side of the equation by simplifying each term.
x=(-y+7)/(2)
