Question

1)-7x^2+52x-85=0
2)x^2+x-12=0
3)-x^2+2x+24=0
4)x^2-12x+36=0

Answer 1

- 7х²+52х-85=0
D/4=26²-7*85=81=+-9²
х₁= (- 26-9)/ -7=35/7=5
х₂=( -26+9)/ -7=17/7=2 3/7

х²+х-12=0
D=1+12*4=25=+-5²
х₁= -1+1/2=0/2=0
х₂= -1-1/2= - 1

- х²+2х+24=0
D/4=1+24=25=+-5²
х₁= -1-5=-6
х₂= -1+5=4

х²-12х+36=0
D/4=36-36=0
х₁=х₂=6