Tìm x €Z
A):3x+12=-36
B):2.(3x-5)=-8
C):10-(4-2x)=20
D);/x/=1
E):/x+1/=2
G):-5-/2-x/=-10
F):-3./x-2/=-9
I):18+/3-4x/=35
Tìm x €Z
A):3x+12=-36
B):2.(3x-5)=-8
C):10-(4-2x)=20
D);/x/=1
E):/x+1/=2
G):-5-/2-x/=-10
F):-3./x-2/=-9
I):18+/3-4x/=35
`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}`
Đáp án:
`↓↓↓`
Giải thích các bước giải:
`a) 3x + 12 = -36 -> 3x = -36 – 12 -> 3x = -48 -> x = -48 : 3 -> x = -16`
`b) 2 (3x – 5) = -8 -> 3x – 5 = -8 : 2 -> 3x – 5 = -4 -> 3x = -4 + 5 -> 3x = 1 -> x = 1 : 3 -> x = 1/3`
`c) 10 – (4 – 2x) = 20 -> 4 – 2x = 10 – 20 -> 4 – 2x = -10 -> 2x = 4 – (-10) -> 2x = 14 -> x = 14 : 2 -> x = 7`
`d) |x| = 1 -> x = ±1`
`e) |x +1| = 2`
`-> x + 1 = 2` hoặc `x + 1 = -2`
`-> x = 1` hoặc `x = -3`
`g) -5 – |2 – x| = -10`
`-> |2 – x| = 5`
`-> 2 – x= 5` hoặc `2 – x = -5`
`-> x = -3` hoặc `x = 7`
`f) -3 |x – 2| = -9`
`-> |x – 2| = 3`
`-> x – 2 = 3` hoặc `x – 2 = -3`
`-> x= 5` hoặc `x = -1`
`l) 18 + |3 – 4x| = 35`
`-> |3 – 4x| = 17`
`-> 3 – 4x = 17` hoặc `3 – 4x = -17`
`-> 4x = -14` hoặc `4x = 20`
`-> x = (-14)/4` hoặc `x = 5`