4x(x+3)=-3和3x^2-3x-1=0

4x(x+3)=-3
4x^2+12x+3=0
(4x+1)(x+3)=0
4x+1=0 或 x+3=0
4x=-1
x1=-1/4
x2=-3
3x^2-3x-1=0
x^2-x-1/3=0
x^2-x-1/3+1/4-1/4=0
(x-1/2)^2-7/12=0
[x-1/2+√（7/12）][x-1/2-√（7/12）]=0
x-1/2+√（7/12）=0 或 x-1/2-√（7/12）=0
x1=1/2-√（7/12)
x2=1/2+√（7/12)