<B + <C = 90
2x + 15 + 5x - 2 = 90
7x + 13 = 90
7x = 77
x = 11
<B = 2x + 15
<B = 2(11) + 15
<B = 22 + 15
<B = 37
Answer
37
∠B = 37°
Since the triangle is right then ∠B + ∠C = 90. hence
2x + 15 + 5x - 2 = 90 (simplify left side )
7x + 13 = 90 ( subtract 13 from both sides )
7x = 77 ( divide both sides by 7 )
x = 11, hence
∠B = (2 × 11 ) + 15 = 22 + 15 = 37°
