Answer: (B) ∠A = 146, ∠B = 21, ∠C = 13
<u>Step-by-step explanation:</u>
∠A = 40x - 14 <em>Given</em>
∠B = 29 - 2x <em>Given</em>
∠C = 9 + x <em>Given</em>
∠A + ∠B + ∠C = 180° <em>Triangle Sum Theorem</em>
(40x - 14) + (29 - 2x) + (9 + x) = 180 <em>Substitution</em>
39x + 24 = 180 <em>Simplify (added like terms)</em>
39x = 156 <em>Subtraction Property of Equality</em>
x = 4 <em>Division Property of Equality</em>
∠A = 40x - 14 = 40(4) - 14 = 160 - 14 = 146
∠B = 29 - 2x <em> </em>= 29 - 2(4) = 29 - 8 = 21
∠C = 9 + x = 9 + 4 = 13