Answer:
y=-5
Step-by-step explanation:
1) Distribute 9 through the parenthesis: -9y-18=9y+72
2) Move variable to the left side and change its sign: -9y-9y-18=72
3) Move constant to the right side and change its sign: -9y-9y=72+18
4) Collect the like terms and add the numbers: -18y=90
5) Divide both sides of the equation by -18: y=-5
