1.(x-1)=4 x-1=正负2 x=3或x=-1 2.x+5x+3=0 △=b-4ac=25-12=13 ∴x=-(b正负√13)/a=-5正负√13 3.3x+6x+1=0 3(x+2x+1)-2=0 3(x+1)=2,(x+1)=2/3 x=-1+√6/3或x=-1-√6/3 4.(x-2)=4(x+1) (x-2)-4(x+1)=0 (x-2-2(x+1))(x-2+2(x+1))=0 x=-4或x=0 望采纳,谢谢