{x^2+6xy+8y^2=91{x+3y-10=0 решите уравнение

Question

{x^2+6xy+8y^2=91{x+3y-10=0 решите уравнение

Answer 1

Вот:
x=10-3y(10-3y)^2+6y(10-3y)+8y^2=91100-60y+9y^2+60y-18y^2+8y^2=91100-y^2=91-y^2=-9y=3x=10-3*3=10-9=1