|3y+7|-10=-5 add 10 to both sides
|3y+7|=5 now since this is an absolute value equation we must solve for both the positive and negative solutions...
3y+7=5 subtract 7 from both sides
3y=-2 divide both sides by 3
y=-2/3
Now
3y+7=-5 subtract 7 from both sides
3y=-12 divide both sides by 3
y=-4
So y=-2/3 and -4