Hello sir please give me the best way for solving the best way for solving the question of class 9th ncert math of Polynomials chapter of exercise 2.5 of math, I don’t know how to solve it please guide me for best solution Write the following cubes in expanded form:(ii) (2a−3b)3
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Using identity,(x–y)3 = x3–y3–3xy(x–y)
(2a−3b)3 = (2a)3−(3b)3–(3×2a×3b)(2a–3b)
= 8a3–27b3–18ab(2a–3b)
= 8a3–27b3–36a2b+54ab2