x+3xy+2xz=x+x(3y+2z)
x+y=5150
y+z=11888 inmultim cu 2
x+y=5150
2y+2z=23776
adunam relatiile
x+y+2y+2z=5150+23776
x+3y+2z=28926
deci 3y+2z=28926-x
inlocuim in prima relatie
x+3xy+2xz=x+x(3y+2z)=x+x(28926-x)=
x+28926x-x^2=28927x-x^2
unde x^2 - x la puterea a doua