what is the solution for x?

4x + 8x = 60 divide each item by 4
x + 2x = 15 simplify
3x = 15 divide each item by 3
x = 5

Answer: x = 5

Proof:
4(5) + 8(5) = 60
20 + 40 = 60
60 = 60

4x + 8x = 60
12x = 60 divide each side by 12
x = 5

12x = 60
x = 5 ------agreed !!

4x + 8x = 60
(4 + 8)x = 60
12x = 60
x = 60/12
x = 5

12x = 60
x= 5
you are correct?

5

You're answer is correct, and your method of solving for x is also right.

I concur!

Yes, you are absolutely right :)