Question

Решите уравнение
1)2x^2-3x-5=0
2)5z^2-2z-3=0
3)-2x^2+13x-21=0
4)-7x^2+5x+2=0

Answer 1

1) D=49; x1=2,5; x2=-1;
2) D=64; x1=1; x2=-0,6;
3) D=1; x1=3; x2=3,5;
4) D=81; x1=-5+9/-14=-4/14=-2/7; x2=1