f: =>2x^2(x+3)-x(x+3)=0
=>x(x+3)(2x-1)=0
=>\(x\in\left\{0;\dfrac{1}{2};-3\right\}\)
g: =>(2x+5)^2=(2x+4)^2
=>(2x+5+2x+4)(2x+5-2x-4)=0
=>4x+9=0
=>x=-9/4
h: =>(x^2+3x)(x^2+3x+2)-3=0
=>(x^2+3x)^2+2(x^2+3x)-3=0
=>(x^2+3x+3)(x^2+3x-1)=0
=>x^2+3x-1=0
=>\(x=\dfrac{-3\pm\sqrt{13}}{2}\)
i: =>(x-2)(x-3)=0
=>x=2 hoặc x=3