-3x²+4x+1=0
3x²-4x-1=0
x = {4±根號(hào)(4^2+4*3)}/(2*3)={2±根號(hào)7} /3
x1 = (2-根號(hào)7) /3
x2 = (2+根號(hào)7) /3
1/2x²+2x-1=0
x²+4x-2=0
(x+2)²=2+4
x+2=±根號(hào)6
x1=-2-根號(hào)6
x2=-2+根號(hào)6
3x²-12x+1/3=0
x²-4x+1/9=0
(x-2)²=4-1/9
x-2=±根號(hào)35 /3
x1 = 2-根號(hào)35 /3
x2 = 2+根號(hào)35 /3
2x²+2.5x-0.5=0
4x²+5x-1=0
x= {-5±根號(hào)(5^2+4*4)}/(2*4) = {-5±根號(hào)41)}/8
x1={-5-根號(hào)41)}/8
x2={-5+根號(hào)41)}/8