3 (2x-5) = 21

What is x?

You would solve a problem like this:

3 (2x-5) = 21

6x-15=21 ... I multiplied 2x and - 5 by 3

6x-15=21

6x-15+15=21+15 ... I added 15 to both sides so 6x can be alone

6x=36

6x/6=36/6 ... I divided by 6 from both sides to leave x alone to get the answer:

x=6.

X=6 is your answer.-.