Question

x^2+6xy+8y^2=91
x+3y-10=0
Помогите :)

Answer 1

{ x² +6xy +8y² =91 ;x+3y -10 =0 .
{(x+3y)² -y² =91 ; x+3y =10.
10² -y² =91;
y²=9 ;
y₁ = -3 ;
y₂ =3.
x = -3y+10 ;
x₁ =( -3)*y₁+10 =(-3)*(-3)+10=19.
x₂ =(-3)*3+10 =1.
ответ :{ (19.; -3) , (1;3) }.