№76 г)х2-12х+20 д)-у2+16у-15 е)-х2-8х+9

Question

№76
г)х2-12х+20
д)-у2+16у-15
е)-х2-8х+9

Answer 1

Г) x^2-12x+20
D=144-4*1*20=144-80=64=8^2
X1=12+8/2=20/2=10
X2=12-8/2=4/2=2
Д) -y^2+16y-15
D=256-4*-1*-15=256-60=196=14^2
Y1=-16+14/-2=-2/-2=1
Y2=-16-14/-2=-30/-2=15
Е) -x^2-8x+9
D=64-4*-1*9=64+36=100=10^2
X1=8+10/-2=-9
X2=8-10/-2=1