Đáp án:
Giải thích các bước giải:
Câu 1:
`a)6x-20=0`
`↔6x=20`
`↔x=10/3`
Vậy `S={10/3}`
`b)` `(5x)/2-(4x)/3=7/6`
`↔(5x.3-4x.2)/6=7/6`
`→15x-8x=7`
`↔7x=7`
`↔x=1`
Vậy `S={1}`
`c)(4x+5)(x-13)=0`
`↔` \(\left[ \begin{array}{l}4x+5=0\\x-13=0\end{array} \right.\) `↔` \(\left[ \begin{array}{l}x=-\dfrac{5}{4}\\x=13\end{array} \right.\)
Vậy `S={-4/5;13}`
`d)10x^2-11x+1=0`
`↔(10x-1)(x-1)=0`
`↔` \(\left[ \begin{array}{l}10x-1=0\\x-1=0\end{array} \right.\) `↔` \(\left[ \begin{array}{l}x=\dfrac{1}{10}\\x=1\end{array} \right.\)
Vậy `S={1/10;1}`
Câu 2:
`a)` `(3x+2)/(x-3)=3+x/(x-3)`
`↔(3x+2)/(x-3)=(3(x-3)+x)/(x-3)`
`→3x+2=3x-9+x`
`↔3x-3x-x=-9-2`
`↔-x=-11`
`↔x=11`
Vậy `S={11}`
`b)` `(x^2+3x)(x^2+4x-5)=0`
`↔x(x+3)(x-1)(x+5)=0`
`↔` \(\left[ \begin{array}{l}x=0\\x+3=0\\x-1=0\\x+5=0\end{array} \right.\) `↔` \(\left[ \begin{array}{l}x=0\\x=-3\\x=1\\x=-5\end{array} \right.\)
Vậy `S={0;1;-3;-5}`
