Bài 2:
a: \(\Leftrightarrow x^2-x-x^2+2x=5\)
=>x=5
b: =>4x(x^2-9)=0
=>x(x-3)(x+3)=0
hay \(x\in\left\{0;3;-3\right\}\)
c: =>(x-1)(2x-x+1)=0
=>(x-1)(x+1)=0
=>x=-1 hoặc x=1
d: \(\Leftrightarrow\left(x^2-9x+14\right)\left(x^2-9x+20\right)=72\)
=>\(\left(x^2-9x\right)^2+34\left(x^2-9x\right)+208=0\)
=>(x^2-9x+8)(x^2-9x+26)=0
=>(x-1)(x-8)=0
=>x=1 hoặc x=8


