Use the FOIL method: \((a+b)(c+d)=ac+ad+bc+bd\).
\[2{x}^{2}+xy+2yx+{y}^{2}+(x+2y)(x-y)\]
Use the FOIL method: \((a+b)(c+d)=ac+ad+bc+bd\).
\[2{x}^{2}+xy+2yx+{y}^{2}+{x}^{2}-xy+2yx-2{y}^{2}\]
Collect like terms.
\[(2{x}^{2}+{x}^{2})+(xy+2xy-xy+2xy)+({y}^{2}-2{y}^{2})\]
Simplify.
\[3{x}^{2}+4xy-{y}^{2}\]
3*x^2+4*x*y-y^2
