1. x² - х - 6 = 0 2. 2х² - 4х - 30 = 0 3. х² + 15х - 100 = 0

Question

1. x² - х - 6 = 0 2. 2х² - 4х - 30 = 0 3. х² + 15х - 100 = 0

Answer 1

1.
d=1*1+4*6=1+24=25
√25=5
x1=(1+5/2)=6/2=3
x2=(1-5/2)=-4/2=-2
2.
d=4*4+4*2*30=16+240=256
√256=16
x1=(4+16/4)=20/4=5
x2=(4-16/4)=-12/4=-3
3.
d=15*15+4*100=225+400=625
√625=25
x1=(-15+25/2)=10/2=5
x2=(-15-25/2)=-40/2=-20

Answer 2

1.D=b^2-4ac
D=1-4•1•(-6)=25, √D=5
x1=-b+√D/2a= 1+5/2= 3
x2=-b-√D/2a=1-5/2= -2
2.D=b^2-4ac
D=16-4•2•(-30)=256, √D=16
x1=-b+√D/2a=4+16/4=5
x2=-b-√D/2a=4-16/4=-3
3. .D=b^2-4ac
D=225-4•1•(-100)=625, √D=25
x1=-b+√D/2a= -15+25/2=5
x2=-b-√D/2a=-15-25/2=-20