a: =>(x-1)(x^2+5x-2)-(x-1)(x^2+x+1)=0
=>(x-1)(x^2+5x-2-x^2-x-1)=0
=>(x-1)(4x-3)=0
=>x=3/4 hoặc x=1
b: =>\(x^2+11x^2-7x+22x-14-4=0\)
=>12x^2+15x-18=0
=>4x^2+5x-6=0
=>4x^2+8x-3x-6=0
=>(x+2)(4x-3)=0
=>x=3/4 hoặc x=-2
c: =>(x+1)(x^2-x+1)-x(x+1)=0
=>(x+1)(x^2-2x+1)=0
=>x=-1 hoặc x=1
d: =>4x^2-10x-2x+5=0
=>(2x-5)(2x-1)=0
=>x=1/2 hoặc x=5/2