+40 Here your task simply is to get y by itself.
start by removing any value on the same side of the equation as y:
ie. 4x - 9y =20 (bring 4x on the other side of the equation by subtracting 4x from both sides)
-> 4x- 4x -9y= 20- 4x which results in:
-> -9y= 20- 4x
Now since we are solving for y and not -9y, we bring the -9 on the other side of the equation by dividing both sides by -9, like:
-> -9y/ -9= (20-4x) / -9
which is:
-> y= (20-4x) / -9
therefore your answer is
y= (20 - 4x) / -9
