Question

If x-5=2 then find the value of 6x-20

Answer 1

First solve the first equation to find x.

x-5=2
x=7

Now plug it in to the other equation to get your answer.

6(7)-20
42-20
22

The answer is 22.

Answer 2

So x in the fist problem is 7. So the x is substituted be 7. guessing you want me  to solve,
6x-20
=6(7)-20
=42-20
=22