3x^2+5x=(3x+5)x=0得x=0或3x+5=0即x= - 5/3
4x^2-4x+1=(2x-1)^2=0得2x-1=0即x=1/2
4x^2-7=0即4x^2=7即x^2=7/4即x=正负根号7除以2
-x^2+2x-3=0即x^2-2x+3=0=(x-1)^2+2=0此方程无解,若为x^2+2x-3=0即为(x-1)*(x+3)=0解得x=1或x= -3
3x^2+5x=(3x+5)x=0得x=0或3x+5=0即x= - 5/3
4x^2-4x+1=(2x-1)^2=0得2x-1=0即x=1/2
4x^2-7=0即4x^2=7即x^2=7/4即x=正负根号7除以2
-x^2+2x-3=0即x^2-2x+3=0=(x-1)^2+2=0此方程无解,若为x^2+2x-3=0即为(x-1)*(x+3)=0解得x=1或x= -3