3x-5y=-3 original problem
3(1)-5y=-3 put 1 in the place of x and multiply
3-5y=-3 subtract 3 from both sides
-5y=-6 divide both sides by -5
y=possitive 6/5
hope that helps
(x+40):12=88-78
(x+40):12=10
x+40=10*12
x+40=120
x=120-40
x=80
You know that a fraction is equivalent is the number multiply or divide into each other. So 4/12 is equivalent to 13 because 4 is a third or 12.