Question

9(x-y)^2 - (x+2y)^2 factorise

Answer 1

$\begin{gathered}\\ \sf\longmapsto 9(x-y)^{2}-(x+2y)^{2}\end{gathered}$

$\begin{gathered}\\ \sf\longmapsto (3(x-y)-(x+2y))\times(3(x-y)+(x+2y))\end{gathered}$

$\begin{gathered}\\ \sf\longmapsto (2x-5y)(4x-y)\end{gathered}$

solved✔︎