Giải phương trình sau:
a) 8(3x-2)-14x=2(4-7x)+15x
b) (3x-1)(x-3)-9+ $x^{2}$ =0
c)$\frac{x+2}{x-2}$-$\frac{3x+5}{2}$=$\frac{2}{x(x-2)}$
Giải phương trình sau:
a) 8(3x-2)-14x=2(4-7x)+15x
b) (3x-1)(x-3)-9+ $x^{2}$ =0
c)$\frac{x+2}{x-2}$-$\frac{3x+5}{2}$=$\frac{2}{x(x-2)}$
Đáp án:
Giải thích các bước giải:
`a) 8(3x-2)-14x=2(4-7x)+15x`
`<=>24x-16-14x=8-14x+15x`
`<=>10x-16=x+8`
`<=>9x=24`
`<=>x=8/3`
Vậy `S={8/3}`
`b)` `(3x-1)(x-3)-9+x^2=0`
`<=>(3x-1)(x-3)+(x^2-9)=0`
`<=>(3x-1)(x-3)+(x-3)(x+3)=0`
`<=>(x-3)(3x-1+x+3)=0`
`<=>(x-3)(4x+2)=0`
`<=>` \(\left[ \begin{array}{l}x-3=0\\4x+2=0\end{array} \right.\) `<=>` \(\left[ \begin{array}{l}x=3\\x=-\dfrac{1}{2}\end{array} \right.\)
Vậy `S={-1/2;3}`
`c)` `(x+2)/(x-2)-(3x+5)/2=2/(x(x-2))` ĐKXĐ: `x\ne2`
`<=>(2x(x+2)-[x(x-2)(3x+5)])/(2x(x-2))=(2.2)/(2x(x-2))`
`=>2x(x+2)-[x(x-2)(3x+5)]=2.2`
`<=>-3x^3+3x^2+14x-4=0`