1) x^2+4x-7=0

2) - x^2+2x-1=0

3) - 3 х^2+13 х+10=0

4) - x^2+4 х+7=0

1) x^2+4x-7=0D=4^2-4 * (-7) = 16+28=44

x1 = (-4-√44) / 2 = (-4-2√11) / 2=-2-√11

x2=-2+√11

2) - x^2+2x-1=0

x^2-2x+1=0

D=4-4=0 - один корень

х1=х2=2/2=1

3) - 3 х^2+13 х+10=0

3 х^2-13x-10=0

D = (13) ^2-4*3 * (-10) = 169+120=289

x1 = (13-√289) / (2*3) = (13-17) / 6=-4/6=-2/3

x2 = (13+17) / 6=30/6=5

4) - x^2+4 х+7=0

x^2-4x-7=0

D = (-4) ^2-4 * (-7) = 16+28=44

x1 = (4-√44) / 2 = (4-2√11) / 2=2-√11

x2=2+√11