alleryFind x and y in 5x − 7y = 2 and 7x − 5y = 22.
A(6, 4)
B(5, 3)
C(7, 2)
D(2, 7)
Answer & Solution
Correct answer: A. (6, 4)
From eq1: x = (2 + 7y)/5. Sub into eq2: 7(2 + 7y)/5 − 5y = 22
⇒ (14 + 49y − 25y)/5 = 22
⇒ 14 + 24y = 110 ⇒ y = 4. Then x = (2 + 28)/5 = 6.
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