z= xcosy+ysinx ,y=x^2+1
5.75Δx+21.5Δy=-39.046875
21.09375Δx-6.75Δy=13.207031
expand f(x, y)=x^2+xy+y^2 (x-1)and (y-2) up to 3rd degree term
xyr-(x²-y²)s-xyt+py-qx=2(x²-y²) canonical from Laplace
X+(3x-2)= 18
6=6:0=
6=6:0
18=24*18640/X
9.2=24*18640/X
360/12 fully simplified
