20x+ 5y = 15
Move 20x to the other side. Sign changes from +20x to -20x
20x-20x+5y=-20x+15
5y=-20x+15
Divide both sides by 5
5y/5=y ( Cross out 5 and 5, divide by 5, 1*1*y=y)
-20/5=-4x
15/5=3
y=-4x+3 or y=3-4x
Answer: y=-4x+3 or y=3-4x
