Answer:
The answer is 4
Explanation:
The angles in a triangle add up to 180 degrees.
You have two angles given 90(right angle) and 57.
Add them to get 147 then subtract from 180.
180 - 147 = 33
Set 33 equal to the expression
33 = 4x + 17
33- 17 = 4x
16 = 4x
4 = x