How do you expand ${(x - 9 y)}^{2}$ $(x-9y)^2$ ?

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Answer 1 · 2016-08-14T06:49:22

$x^{2} - 18 x y + 81 y^{2}$ $x^2-18xy+81y^2$ .

We use the Formula $: {(a - b)}^{2} = a^{2} - 2 a b + b^{2}$ $: (a-b)^2=a^2-2ab+b^2$ .

Hence, ${(x - 9 y)}^{2} = x^{2} - 2 \cdot x \cdot 9 y + {(9 y)}^{2}$ $(x-9y)^2=x^2-2*x*9y+(9y)^2$

$= x^{2} - 18 x y + 81 y^{2}$ $=x^2-18xy+81y^2$ .

How do you expand (x−9y)2(x-9y)^2?