To solve this problem, we know that the sum of the two adjacent angles must be equal to 90°, since they are inside a 90° angle.
Therefore, we can write the following equation:
(x+4) + (3x+2) = 90
Simplify the equation by combining like terms:
4x + 6 = 90
Subtract 6 from both sides:
4x = 84
Divide both sides by 4 to solve for x:
x = 21
Therefore, x = 21.