the question asked to find the local extrema for f(x,y) =-x 2 + xy - 2y 2 + x + 10y - 5 I know we have to find fx fy and solve the system of

 the question asked to find the local extrema for f(x,y) =-x2 + xy - 2y2 + x + 10y - 5 I know we have to find fx & fy and solve the system of equations to derive at the critical point but I am a little rusty at using the substitution & elimination method can some be so kind to refresh my memory. I got as far fx = -2x + y +1 & fy = x - 4y +10 and I set them both to zero in the system of equations format. 

F(x,y)=-x2+xy-2y2+x+10y-5 Step1: find the critical pointsFx=-2x+y+1=0………………equation 1Fy=x-4y+10=0……………..equation 2 From equation 1;...