Answer:
x = 16
Explanation:
*A triangle's interior angles always add up to 180 degrees*
1. The square on the left-hand side means 90 degrees
2. To find the degrees on the 150 degrees side we need to subtract 180 from 150 as the line it's on equals 180 degrees
180 -151 = 29
3. Now we know 3 out of the two angles, so if we add them up and subtract them from 180 degrees we will have the 3rd angle
29 +90 = 119
180 - 119 = 61
4. Now we can put that in with the equation
4x + 3 = 61
5. Solve
4x - 3 = 61
+ 3 +3
4x = 64
/4 /4
x = 16