Đáp án-Giải thích các bước giải:
`f) 3x(25x+15)-35(5x+3)=0`
`<=>3x.5(5x+3)-35(5x+3)=0`
`<=>(5x+3)(15x-35)=0`
`<=>` \(\left[ \begin{array}{l}5x+3=0\\15x-35=0\end{array} \right.\) \(\left[ \begin{array}{l}x=-\dfrac35\\x=\dfrac73\end{array} \right.\)
`g)(2x-1)^2+(2-x)(2x-1)=0`
`<=>(2x-1)(2x-1+2-x)=0`
`<=>(2x-1)(x+1)=0`
`<=>x=1/2;x=-1`
`h)(x+2)(3-4x)=x^2+4x+4`
`<=>(x+2)(3-4x)-(x+2)^2=0`
`<=>(x+2)(3-4x-x-2)=0`
`<=>(x+2)(1-5x)=0`
`<=>x=-2;x=1/5`
`i)x^2+(x+2)(11x-7)=4`
`<=>(x^2-4)+(x+2)(11x-7)=0`
`<=>(x-2)(x+2)+(x+2)(11x-7)=0`
`<=>(x+2)(x-2+11x-7)=0`
`<=>(x+2)(12x-9)=0`
`<=>x=-2;x=3/4`
`j) 4x^2-12x+5=0`
`<=>4x^2-10x-2x+5=0`
`<=>2x(2x-5)-(2x-5)=0`
`<=>(2x-5)(2x-1)=0`
`<=>x=5/2;x=1/2`
