Answer:55 degrees
Step-by-step explanation: We are dealing with a right angle which is also the same as a complementary angle that adds up to 90 degrees.
The following equation can be obtained from the right angle
(x-20)+x=90
Simplifying like terms
2x-20=90
We want to solve for x this means we want to get x terms on its own.
We need for -20 to disappear the only way to do this is to add 20. What we do to one side we must do to the other.
2x-20+20=90+20
2x=110
To solve for x we need to divide both sides by 2
2x/2=110/2
x=55 degrees