InterviewSolution
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InterviewSolution
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Show that(i) (3x + 7)2 − 84x = (3x − 7)2 (ii) (9p − 5q)2 + 180pq = (9p + 5q)2 |
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Answer» (i) L.H.S = (3x + 7)2 − 84x = (3x)2 + 2(3x)(7) + (7)2 − 84x = 9x2 + 42x + 49 − 84x = 9x2 − 42x + 49 R.H.S = (3x − 7)2 = (3x)2 − 2(3x)(7) +(7)2 = 9x2 − 42x + 49 L.H.S = R.H.S (ii) L.H.S = (9p − 5q)2 + 180pq = (9p)2 − 2(9p)(5q) + (5q)2 − 180pq = 81p2 − 90pq + 25q2 + 180pq = 81p2 + 90pq + 25q2 = (9p)2 + 2(9p)(5q) + (5q)2 = 81p2 + 90pq + 25q2 L.H.S = R.H.S |
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