x = 12°
Step-by-step explanation:The sum of angles in a triangle = 180 degrees
(2x + 1)° + (5x + 5)° + 90° = 180°
open the bracket and collect like terms
2x + 1 + 5x + 5 + 90 = 180
2x + 5x + 1 + 5 + 90 =180
7x + 96 = 180
7x = 180 - 96
7x = 84
Divide both sides by 7:
7x/7 = 84/7
x = 12°