InterviewSolution
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InterviewSolution
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Subtract :(i) -5y2 from y2(ii) 6xy from – 12xy(iii) (a – b) from (a + b)(iv) a(b – 5) from b(5 – a)(v) -m2 + 5mn from 4m2 – 3mn + 8(vi) -x2 + 10x – 5 from 5x – 10(vii) 5a2 – 7 ab + 5b2 from 3ab – 2a2 – 2b2(viii) 4pq – 5q2 – 3p2 from 5p2 + 3q2 – pq |
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Answer» (i) -5y2 from y2 = y2 – (-5y2) = y2 + 5y2 = 6y2 (ii) 6xy from – 12xy = -12xy – (6xy) = -12xy – 6xy = -18xy (iii) (a – b) from (a + b) = a + b – (a – b) = a + b - a + b = 2b (iv) a(b – 5) from b(5 – a) = ab – 5a from 5b – ab = (5b – ab) – (ab – 5a) = 5b – ab – ab + 5a = 5a – 5b – 2ab (v) -m2 + 5mn from 4m2 – 3mn + 8 = (4m2 – 3mn + 8) – (-m2 + 5mn) = 4m2 – 3mn + 8 + m2 – 5mn = 4m2 + m2 – 3mn – 5mn + 8 = 5m2 – 8mn + 8 (vi) -x2 + 10x – 5 from 5x – 10 = (5x – 10) – (-x2 + 10x – 5) = 5x – 10 + x2 – 10x + 5 = 5x – 10x + x2 – 10 + 5 = x2 – 5x – 5 (vii) 5a2 – 7 ab + 5b2 from 3ab – 2a2 – 2b2 = (3ab – 2a2 – 2b2) – (5a2 – 7ab + 5b2) = 3ab – 2a2 – 2b2 – 5a2 + 7ab – 5b = -2a2 – 5a2 – 2b2 – 5b2 + 7ab + 3ab = -7a2 – 7b2 + 10ab (viii) 4pq – 5q2 – 3p2 from 5p2 + 3q2 – pq = (5p2 + 3q2 – pq) – (4pq – 5q2 – 3p2) = 5p2 + 3q2 – pq2 – 4pq + 5q2 + 3p2 = 5p2 + 3p2 + 3q2 + 5q2 – 4pq – pq = 8p2 + 8q2 – 5pq |
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