Question

If 3x - 1 = 11, what is the value of x 2 + x?

Answer 1

The first equation tells you, after some rearrangement, that x = 4. Use that value of x to evaluate x^2 + x

Answer 2

isolate x first by adding one to both sides

you should get 3x=12
divide both sides by 3 to get x=4
then substitute and get
(4)^2 + 4