Question

factorise x2 +2xy+y2-1

Answer 1

so easy

x2 +2xy+y2-1

(x+y)2 - 1

(x+y-1) (x+y+1)

Answer 2

$\begin{gathered}{x }^{2} + 2xy + {y}^{2} - 1 \\ = {(x + y)}^{2} - {(1)}^{2} \\ = (x + y + 1)(x + y - 1)\end{gathered}x2+2xy+y2−1=(x+y)2−(1)2=(x+y+1)(x+y−1)</p><p>$