`text{ Andor }`
Đáp án:
a) `3x+12=-36`
`3x=-36-12`
`3x=-48`
`x=16`
Vậy `x=16`
b)`2.(3x-5)=-8`
`(3x-5)=-8:2`
`3x-5=-4`
`3x=(-4)-5`
`3x=-9`
`x=-3`
Vậy `x=-3`
c) `10-(4-2x)=20`
`(4-2x)=20+10`
`4-2x=30`
`2x=30+4`
`2x=34`
`x=17`
Vậy `x=17`
d) `|x|=1`
`|x|=1 ⇒ x=1 or x=-1`
e) `|x+1|=2`
\(\left[ \begin{array}{l}x+1=2\\x+1=-2\end{array} \right.\)
\(\left[ \begin{array}{l}x=2-1\\x=(-2)-1\end{array} \right.\)
\(\left[ \begin{array}{l}x=1\\x=-3\end{array} \right.\)
Vậy `x={1;-3}`
g) `-5-|2-x|=-10`
`|2-x|=(-10)+(-5)`
`|2-x|=-15`
\(\left[ \begin{array}{l}2-x=15\\2-x=-15\end{array} \right.\)
\(\left[ \begin{array}{l}x=-13\\x=17\end{array} \right.\)
Vậy `x={-13;17}`
f) `-3.|x-2|=-9`
`|x-2|=(-9):(-3)`
`|x-2|=3`
\(\left[ \begin{array}{l}x-2=3\\x-2=-3\end{array} \right.\)
\(\left[ \begin{array}{l}x=5\\x=-1\end{array} \right.\)
i) `18+|3-4x|=35`
`|3-4x|=35-18`
`|3-4x|=17`
\(\left[ \begin{array}{l}3-4x=17\\3-4x=-17\end{array} \right.\)
\(\left[ \begin{array}{l}x=\frac{-7}{2} \\x=5\end{array} \right.\)
Vậy `x={` $\frac{-7}{2}$ `; 5}`
