Show your work,

10-5x = 20

10-5x=20

-10 - 10

-5x=10

-5 = - 5

x=-2

The best part of this problem is that it has one unknown variable in the form of "x" and a single equation. So getting to the desired solution becomes very easy.

The equation given in the question is

10 - 5x = 20

- 5x = 20 - 10

- 5x = 10

- x = 10/5

- x = 2

Multiplying both sides with - 1 we get

x = - 2

So the value of x is - 2. I hope the procedure is clear enough for you to understand.