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a: \(\left|x\right|-\dfrac{38}{7}\left|x\right|-\dfrac{3}{4}=2\left|x\right|-\dfrac{8}{7}\)
\(\Leftrightarrow\left|x\right|\cdot\dfrac{-45}{7}=-\dfrac{8}{7}+\dfrac{3}{4}=\dfrac{-32+21}{28}=\dfrac{-11}{28}\)
=>|x|=11/180
=>x=11/180 hoặc x=-11/180
b: \(\Leftrightarrow x\cdot\dfrac{13}{4}-\dfrac{7}{6}x=\dfrac{5}{12}+\dfrac{5}{3}\)
=>25/12x=25/12
hay x=1
câu 1 bỏ dấu ngoặc rồi tính
( 36 + 79 ) + ( 145 _ 79 _ 36 )
\(=36+79+145-79-36\)
\(=\left(36-36\right)+\left(79-79\right)+145\)\
\(=0+0+145=145\)
10 _ [ 12 _ ( -9 _ 1 ) ]
\(=10-12-10\)
\(=10-10-12\)
\(=0-12=-12\)
( 38 _ 29 + 43) _ ( 43 + 38 )
\(=38-29+43-43-38\)
\(=\left(38-38\right)+\left(43-43\right)-29\)
\(=0+0-29=-29\)
271 _ [ ( -43 ) + 271 _ ( -17 ) ]
\(=271+43-271-17\)
\(=\left(271-271\right)+\left(43-17\right)\)
\(=0+26=26\)
- 144 _ [ 29 _ ( + 144 ) _ ( + 144 )]
\(=-144-19+144+144\)
\(=\left(-144+144+144\right)-19\)
\(=144-19=125\)
đợi mk lm tiếp câu 2 nha .
bài 2 tính tổng các số nguyên
- 18 < hoặc bằng x < hoặc bằng 17
\(\Rightarrow x\in\left\{-18;-17;-16;....;17\right\}\)
tổng \(x=-18+\left(-17\right)+\left(-16\right)+...+17=-18\)
- 27 < hoặc bằng x < hoặc bằng 27
\(\Rightarrow x\in\left\{-27;-26;-25;..;27\right\}\)
Tổng \(x=-27+\left(-26\right)+\left(-25\right)+...+27=0\)
a, \(3\left(x-1\right)-\left(2x+3\right)=5\)
\(\Rightarrow3x-3-2x-3=5\)
\(\Rightarrow x-6=5\)
\(\Rightarrow x=11\)
b, \(\frac{6}{13}=\frac{x}{7}\)
\(\Rightarrow x=\frac{6}{13}.7\)
\(\Rightarrow x=\frac{42}{13}\)
c, \(|x|=4\)
\(\Rightarrow x=4\)hoặc \(x=-4\)
d,, \(|x-2|+5=10\)
\(Th1:x-2>0\)
\(\Rightarrow x-2+5=10\)
\(\Rightarrow x+3=10\)
\(\Rightarrow x=7\)
\(Th2;x-2< 0\)
\(\Rightarrow2-x+5=10\)
\(\Rightarrow7-x=10\)
\(\Rightarrow x=-3\)
e, \(3|x-1|-6=9\)
\(Th1:x-1>0\)
\(\Rightarrow3\left(x-1\right)-6=9\)
\(\Rightarrow3x-3-6=9\)
\(\Rightarrow3x-9=9\)
\(\Rightarrow3x=18\)
\(\Rightarrow x=6\)
\(Th2:x-1< 0\)
\(\Rightarrow3\left(1-x\right)-6=9\)
\(\Rightarrow3-3x-6=9\)
\(\Rightarrow-3x-3=9\)
\(\Rightarrow-3x=12\)
\(\Rightarrow x=-4\)
a) 5x=-15 <=> x=-3
b) 1-2x=37 <=> 2x=-36 <=> x=-18
c) 2x=-57 <=> x=-57/2
\(\left(6x-16\right).7^8=2.7.7^8\Leftrightarrow6x-16=14\Leftrightarrow6x=30\Leftrightarrow x=5\)
4-(7-x)=x-(13-4)
4-7+x= x-13+4
-3+x=x-9
-3+x=-9+x<vo li>
=> x ko co gtri thoa man
4-(7-x)=x-(13-4)
4-7+x=x-13+4
-3+x=x-9
-3+x=-9+x
Mà -3+x không thể bằng -9+x
Suy ra: không có giá trị x.
1,
7-3/5x=4+7/3-4/3
7-3/5x=5
3/5x=7-5
3/5x=2
x=2:3/5
x=10/3
2,
13+(9/15+20/15)x=18+21
13+29/15x=39
29/15x=39-13
29/15x=26
x=26:29/15
x=390/29
3,
Vì M là trung điểm của đoạn AB nên M nằm giữa Avà B
=>MA=MB=1/2AB=1/2.8=4(cm)
6/13x7/29+6/13x22/9
6/13x(7/29+22/9)
6/13x701/261
1402/1131
a) \(\dfrac{2}{3}x-\dfrac{1}{2}=\dfrac{1}{10}\)
\(\dfrac{2}{3}x=\dfrac{1}{10}+\dfrac{1}{2}=\dfrac{3}{5}\)
\(x=\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{9}{10}\)
b) \(\dfrac{39}{7}:x=13\)
\(x=\dfrac{\dfrac{39}{7}}{13}=\dfrac{3}{7}\)
c) \(\left(\dfrac{14}{5}x-50\right):\dfrac{2}{3}=51\)
\(\dfrac{14}{5}x-50=51\cdot\dfrac{2}{3}=34\)
\(\dfrac{14}{5}x=34+50=84\)
\(x=\dfrac{84}{\dfrac{14}{5}}=30\)
d) \(\left(x+\dfrac{1}{2}\right)\left(\dfrac{2}{3}-2x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\\dfrac{2}{3}-2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)
e) \(\dfrac{2}{3}x-\dfrac{1}{2}x=\dfrac{5}{12}\)
\(\dfrac{1}{6}x=\dfrac{5}{12}\)
\(x=\dfrac{5}{12}:\dfrac{1}{6}=\dfrac{5}{2}\)
g) \(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\dfrac{11}{5}-\dfrac{3}{7}=-2\)
\(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\cdot\dfrac{11}{5}=-2+\dfrac{3}{7}=-\dfrac{11}{7}\)
\(x\cdot\dfrac{44}{7}+\dfrac{3}{7}=-\dfrac{11}{7}:\dfrac{11}{5}=-\dfrac{5}{7}\)
\(\dfrac{44}{7}x=-\dfrac{5}{7}-\dfrac{3}{7}=-\dfrac{8}{7}\)
\(x=-\dfrac{8}{7}:\dfrac{44}{7}=-\dfrac{2}{11}\)
h) \(\dfrac{13}{4}x+\left(-\dfrac{7}{6}\right)x-\dfrac{5}{3}=\dfrac{5}{12}\)
\(\dfrac{25}{12}x-\dfrac{5}{3}=\dfrac{5}{12}\)
\(\dfrac{25}{12}x=\dfrac{5}{12}+\dfrac{5}{3}=\dfrac{25}{12}\)
\(x=1\)
Mỏi tay woa bn làm nốt nha!!
( 7x -22) : 4 = 13 +6 =19
7x-22= 19.4=76
7x = 76+22=98
x = 98 : 7 =14
tick ủng hộ mình nha các bạn