Question

1)5x^2+4x-1=0
2)3x^2+10x+7=0
3)28x^2-36x+11=0

Answer 1

1) 5х^2+4х-1=0
D=4^2-4*5*(-1)=16+20=36
x1,2=(-4+-6) / 10
x1= 1/5, x2=-1

2) 3x^2+10x+7=0
D=10^2-4*3*7=100-84=16
x1,2=(-10+-4) / 9
x1=-2/3, x2=-14/9

3) 28x^2-36x+11=0
D=(-36)^2-4*28*11=1296-1232=64
x1,2=(36+-8) / 56
x1=11/14, x2=1/2