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Ta có:
\(37 - 5 \left(\right. x + 9 \left.\right) = \mid - 17 \mid\)
👉 Vì \(\mid - 17 \mid = 17\)
⇒ \(37 - 5 \left(\right. x + 9 \left.\right) = 17\)
\(37 - 5 x - 45 = 17\) \(- 5 x - 8 = 17\) \(- 5 x = 25 \Rightarrow x = - 5\)
✅ Đáp án: x = -5
b)
\(- 2 < \mid x + 2 \mid < 2\)
👉 Vì \(\mid x + 2 \mid \geq 0\) nên điều kiện \(- 2 < \mid x + 2 \mid\) luôn đúng
⇒ chỉ cần:
\(\mid x + 2 \mid < 2\) \(- 2 < x + 2 < 2\) \(- 4 < x < 0\)
✅ Đáp án: \(- 4 < x < 0\)
c)
\(- 7 \mid x - 2013 \mid + 20120 = \mid + 1 \mid\)
👉 \(\mid + 1 \mid = 1\)
⇒
\(- 7 \mid x - 2013 \mid + 20120 = 1\) \(- 7 \mid x - 2013 \mid = 1 - 20120 = - 20119\) \(\mid x - 2013 \mid = \frac{20119}{7} = 2874.142857...\)
⇒
\(x - 2013 = \pm \frac{20119}{7}\) \(x = 2013 \pm \frac{20119}{7}\)
👉 Có 2 nghiệm:
- \(x = 2013 + \frac{20119}{7}\)
- \(x = 2013 - \frac{20119}{7}\)
(= khoảng 4887.14 và -861.14)
d)
\(21 + \left(\right. x - 10 \left.\right) = - 19\)
\(21 + x - 10 = - 19\) \(x + 11 = - 19\) \(x = - 30\)
✅ Đáp án: x = -30
✅ Tóm lại:
- a) \(x = - 5\)
- b) \(- 4 < x < 0\)
- c) \(x = 2013 \pm \frac{20119}{7}\)
- d) \(x = - 30\)
a)\(=\frac{-5}{2}:\left(\frac{3}{4}-\frac{2}{4}\right)\)
\(=\frac{-5}{2}:1=\frac{-5}{2}\)
b)\(=\frac{146}{13}-\left(\frac{18}{7}+\frac{68}{13}\right)\)
\(=\frac{146}{13}-\frac{18}{7}-\frac{68}{13}\)
\(=\frac{146}{13}-\frac{68}{13}-\frac{18}{7}\)
\(=\frac{78}{13}-\frac{18}{7}=6-\frac{18}{7}=\frac{42}{7}-\frac{18}{7}=\frac{24}{7}\)
c)\(=\left(\frac{-5}{24}+\frac{18}{24}+\frac{14}{24}\right):\left(\frac{-9}{4}\right)^2\)
\(=\frac{27}{24}:\frac{\left(-9\right)^2}{4^2}\)
\(=\frac{27\times16}{24\times81}=\frac{2}{9}\)
\(2\left(x-5\right)-3\left(x-4\right)=-6+15.\left(-3\right)\)
\(2x-10-3x+12=-51\)
\(2-x=-51\)
\(\Rightarrow x=2-\left(-51\right)=53\)
vậy x=53
\(2\left(x-5\right)-3\left(x-4\right)=-6+15.\left(-3\right)\)
\(\Leftrightarrow2x-10-3x+12=-51\)
\(\Leftrightarrow\left(2x-3x\right)-\left(10-12\right)=51\)
\(\Leftrightarrow-x-\left(-2\right)=-51\)
\(\Leftrightarrow-x+2=-51\)
\(\Rightarrow-x=-53\)
\(\Rightarrow x=53\)
--------Nhớ k cho mk nha bạn. Mk trả lời sớm nhất ak mà chắc cx đúng r ak nên hứa là phải k nha!!ღღღღღ---------------
1/
\(A\)dương \(\Leftrightarrow\)\(\hept{\begin{cases}\left(x-\frac{1}{2}\right)>0\\x-\frac{4}{5}>0\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x>0+\frac{1}{2}\\x>0+\frac{4}{5}\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x>\frac{1}{2}\\x>\frac{4}{5}\end{cases}}\Leftrightarrow x>0,8\)
2/ Làm tương tự nhưng có 2 trường hợp nên bạn làm từng trường hợp nhé ..!
1/a) 12 - x= 1-(-5)
12 - x = 6
x= 12-6
x=6
b)| x+4|= 12
x+4 = \(\pm\)12
*x+4=12
x=8
*x+4= -12
x=-16
2/Tìm n
\(n-5⋮n+2\)
=> \(n+2-7⋮n+2\)
mà \(n+2⋮n+2\)
=> 7\(⋮\)n+2
=> n+2 \(\varepsilon\)Ư(7)= {1;-1;7;-7}
| n+2 | 1 | -1 | 7 | -7 |
| n | -1 | -3 | 5 | -9 |
3/a)4.(-5)2 + 2.(-12)
= 2.2.(-5)2 + 2.(-12)
=2[2.25.(-12)]
=2.(-600)
=-1200
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a) \(-7.\left|x-2013\right|+2012^0=\left|+1\right|\)
\(\Leftrightarrow-7.\left|x-2013\right|+1=1\)
\(\Leftrightarrow-7.\left|x-2013\right|=0\)
\(\Leftrightarrow\left|x-2013\right|=0\)
\(\Leftrightarrow x-2013=0\)
\(\Leftrightarrow x=2013\)
Vậy x = 2013
a) -7.|x-2013| + 20120 = |+1|
-7.|x-2013| + 1 = 1
=> -7.|x-2013| = 0
=> | x-2013| = 0
=> x - 2013 = 0
x = 2013
\(-7.\left|x-2013\right|+1=\left|+1\right|\)
\(-7\left|x-2013\right|+1=1\)
\(-7\left|x-2013\right|=1-1\)
\(-7\left|x-2013\right|=0\)
\(\Rightarrow\left|x-2013\right|=0\)
\(\Rightarrow x-2013=0\)
\(x=2013\)
Vậy \(x=2013\)