10 Factorise [Hint:- Use suitable identity]:- a) Acirc; nbsp;x4-100 Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp;c) Acirc; nbsp;y4-81b) Acirc; nbsp;1604-81b4 Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp; Acirc; nbsp;d) Acirc; nbsp;49x2-121y2

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a) x^{4} - 100 = {(x^{2})}^{2} - 10^{2} = (x^{2} - 10) (x^{2} + 10) [using a^{2} - b^{2} = (a + b) (a - b)] = (x^{2} + 10) (x^{2} - {(\sqrt{10})}^{2}) = (x^{2} + 10) (x - \sqrt{10}) (x + \sqrt{10}) [using a^{2} - b^{2} = (a + b) (a - b)] c) y^{4} - 81 = {(y^{2})}^{2} - 9^{2} = (y^{2} - 9) (y^{2} + 9) [using a^{2} - b^{2} = (a + b) (a - b)] = (y^{2} + 9) (y^{2} - 3^{2}) = (y^{2} + 9) (y - 3) (y + 3) [using a^{2} - b^{2} = (a + b) (a - b)] d) 49 x^{2} - 121 y^{2} = {(7 x)}^{2} - {(11 y)}^{2} = (7 x - 11 y) (7 x + 11 y) [using a^{2} - b^{2} = (a + b) (a - b)]

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