3(4 - 3s) = 30
First, divide both sides by 3.
Second, since 10 goes into 3 to get 30, simplify the fraction to 10.
Third, subtract 4 from both sides.
Fourth, subtract 10 - 4.
Fifth, divide both sides by -3.
Sixth, simplify to turn the whole fraction into a negative.
Seventh, since 2 goes into 3 to get 6, simplify the fraction to 2.

Answer:
s = -2