Question

x+4 * x = 80

Answer 1

5x = 80
x = 80/5 = 16

Answer 2

how?

Answer 3

did you get to 5x?

Answer 4

If you add one more x to 4x, then how many x do you have? ;)

Answer 5

so it would be 4x TIMES x = 5x?

Answer 6

No no, 4x TIMES x = 4x^2. But x PLUS 4x = 5x.
4x is the same as x + x + x + x.
Add another x on, and you get x + x + x + x + x = 5x.

Answer 7

x + 4x = 80
(1 + 4)x = 80
5x = 80
x = 80/5
x = 16