4(y - 3) + 9 - 3y
to distribute, u multiply the number outside of the parenthesis, by everything in the parenthesis.
4(y - 3) = 4*y - 4*3 = 4y - 12
so now we have : 4y - 12 + 9 - 3y....and since there is no equal sign, all we can do now is combine like terms resulting in : y - 3