$$ (x+a)^n = \sum_{k=0}^n \binom{n}{k} x^k a^{n-k} $$ $$(क)\ \frac{a}{a-b} + \frac{b}{b-a}$$    $$\ \frac{a}{a-b} + \frac{b}{-(a-b)} $$ $$(ख)\ \frac{1}{b-… Next page