数学题找人解决!

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