Question 519041
x = measure of angle A
90 - x = complement of angle A {complementary angles add up to 90°}
180 - x = supplement of angle A {supplementary angles add up to 180°}


3(90 - x) = 180 - x - 60 {three times complement is 60 less than supplement}
270 - 3x = 120 - x {used distributive property on left, combined like terms on right}
150 - 3x = -x {subtracted 120 from both sides}
150 = 2x {added 3x to both sides}
x = 75 {divided both sides by 2}


angle A = 75°
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