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    Question

    Find the value of 'a' and 'b' which satisfy the

    following equations: 9a + 7b = 30 4a - 5b = 62
    A a = 6 and b = - 8 Correct Answer Incorrect Answer
    B = - 8 and b = 6 a Correct Answer Incorrect Answer
    C a = 8 and b = - 6 Correct Answer Incorrect Answer
    D a = - 6 and b = 8 Correct Answer Incorrect Answer

    Solution

    9a + 7b = 30 ---------- (I) 4a - 5b = 62 ---------- (II) On solving 5 X equation I + 7 X equation II, We get, 5 X (9a + 7b) + 7 X (4a - 5b) = 5 X 30 + 7 X 62 Or, 45a + 35b + 28a - 35b = 150 + 434 Or, 73a = 584 Or, 'a' = 8 On putting value of 'a' in equation I, We get, 9 X 8 + 7b = 30 Or, 72 + 7b = 30 Or, 7b = - 42 Or, 'b' = - 6

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