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Subtract:(i) -5xy from 12xy(ii) 2a2 from -7a2(iii) 2a-b from 3a-5b(iv) 2x3 – 4x2 + 3x + 5 from 4x3 + x2 + x + 6(v) 3/2y3 – 2/7y2 – 5 from 1/3y3 + 5/7y2 + y – 2 |
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Answer» (i) -5xy from 12xy = 12xy – (- 5xy) = 5xy + 12xy = 17xy (ii) 2a2 from -7a2 = 2a2 + (-7a2) = -2a2 + 7a2 = -9a2 (iii) 2a - b from 3a-5b = -(2a – b)+ (3a – 5b) = -2a + b+ 3a – 5b = a – 4b (iv) 2x3 – 4x2 + 3x + 5 from 4x3 + x2 + x + 6 = – (2x3 – 4x2 + 3x + 5) + (4x3 + x2 + x + 6) = – 2x3 + 4x2 – 3x – 5 + 4x3 + x2 + x + 6 = 2x3 + 5x2 – 2x + 1 (v) 3/2y3 – 2/7y2 – 5 from 1/3y3 + 5/7y2 + y – 2 = 1/3y3 + 5/7y2 + y – 2 – 2/3y3 + 2/7y2 + 5 = 1/3y3 – 2/3y3 + 5/7y2 + 2/7y2 + y – 2 + 5 = -1/3y3 + 7/7y2 + y + 3 = -1/3y3 + y2 + y + 3 |
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