Đáp án:
Giải thích các bước giải:
`a,`
`3(x-2) = 7(10-4x)`
`-> 3x - 6 = 70 - 28x`
`-> 3x = -28x + 76`
`-> 31x = 76`
`-> x = 76/31`
Vậy `x \in {76/31}`
`b,`
`2x^3+5x^2+3x=0`
`-> x(2x^2+5x+3) = 0`
`-> x(x+1)(2x+3) = 0`
`->`\(\left[ \begin{array}{l}x=0\\x+1=0\\2x+3=0\end{array} \right.\)
`->`\(\left[ \begin{array}{l}x=0\\x=-1\\x=-\dfrac32\end{array} \right.\)
Vậy `x \in {0,-1,-3/2}`
`c,`
`(x+3)(2x-1)=4(x+3)`
`-> (x+3)(2x-1) - 4(x+3) = 0`
`-> (x+3)(2x-5) = 0`
`->`\(\left[ \begin{array}{l}x+3=0\\2x-5=0\end{array} \right.\)
`->`\(\left[ \begin{array}{l}x=-3\\x=\dfrac52\end{array} \right.\)
Vậy `x \in {-3,5/2}`
`d,`
`x(x-2)-3x+6=0`
`-> x^2-5x+6=0`
`-> (x^2-2x)+(-3x+6) = 0`
`-> x(x-2) - 3(x-2) = 0`
`-> (x-2)(x-3) = 0`
`->`\(\left[ \begin{array}{l}x-2=0\\x-3=0\end{array} \right.\)
`->`\(\left[ \begin{array}{l}x=2\\x=3\end{array} \right.\)
Vậy `x \in {2,3}`
