Решите систему уравнение 1) 2xy-x=7 x-5y=2 2) 2x^2-xy=33 4x-y=17 3) x^2+2y=18 3x=2y

1) x=5y+22 (5y+2) -y=710y+4-y=79y=3y=1/3 => x=5*1/3=5/3 3) x^2+3x=18x^2+3x-18=0D=9-4*(-18)=9+72=81x (1)=(-3+9) /2 => x (1)=3,5 => y (1) => 3*3,5=2y => y (1)=5,25 x (2)=(-3-9) /2 => x (2)=-6 => y (2) => 3*(-6)=2y => y (2)=-92) y=4x-17 2x^2-x (4x-17)=332x^2-4x^2-17x-33=0-2x^2-17x-33=0D=289 — 4*(-2)*(-33)=289 — 264=25x (1)=(17+5) /-4=-5,5 => y (1)=4*(-5,5) -17 => y (1)=-39x (2)=(17-5) /-4=-3 => y (2)=4*(-3) -17 => y (2)=-29