3(x−1) = 27
I need the answer

You need to isolate/get the variable "x" by itself in the equation:

3(x - 1) = 27        First divide 3 on both sides

x - 1 = 9     Add 1 on both sides to get "x" by itself

x - 1 + 1 = 9 + 1

x = 10

PROOF

3(x - 1) = 27     Substitute/plug in 10 for "x"

3(10 - 1) = 27

3(9) = 27

27 = 27