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