[tex]x=-1,\ \ \ y=2\\\\-2x^2+2x+7y^2+x^2-3x-6y^2+x=-x^2+y^2\\\\-x^2+y=-(-1)^2+2=-1+2=1\\\\\\5xy^2-xy-x^2y-xy^2+2xy+x^2y-4xy^2=xy\\\\xy=(-1)*2=-2\\\\\\-3x^2+7xy*x+2x*x-5x*xy+x^2=-3x^2+7x^2y+2x^2-5x^2y+x^2=2x^2y\\\\2x^2y=2*(-1)^2*2=2*1*2=4\\\\\\[/tex]
[tex]6x*x^2-4x^2*2x-3x*x+x*2x*x+3x=6x^3-8x^3-3x^2+ 2x^3+3x=\\\\=-3x^2+3x\\\\-3x^2+3x=-3*(-1)^2+3*(-1)=-3-3=-6\\\\\\-5xy^3+x^2y^2-3y^2*xy+2y*4xy^2-2xy*3yx=\\\\=-5xy^3+x^2y^2-3xy^3+8xy^3-6x^2y^2=-5x^2y^2\\\\-5x^2y^2=-5*(-1)^2*2^2=-5*1*4=-20[/tex]
