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1,\(54.\left(23-11\right)+23.\left(-22-54\right)\)
\(=54.12+23.\left(-76\right)\)
\(=648-1748\)
\(=-1100\)
2,\(-7+2x=-17-\left(-36\right)\)
\(=>-7+2x=-17+36\)
\(=>-7+2x=19\)
\(=>2x=19+7=26\)
\(=>x=\frac{26}{2}=13\)
3,\(5⋮2a+3\)
\(=>2a+3\inƯ\left(5\right)\)
\(=>2a+3\in\left\{-1;-5;1;5\right\}\)
\(=>2a\in\left\{-4;-8;-2;2\right\}\)
\(=>a\in\left\{-2;-4;-1;1\right\}\)
Vậy ...
54 . ( 23 - 11 ) + 23 . ( -22 - 54 )
=54.23-54.11+23.-22-23.54
=-54.11+23.-22
=-22(27+23)
=-22.50
=-1100
-7 + 2x = -17 - ( -36 )
-7+2x=-17+36
-7+2x+17-36=0
-26+2x=0
2x=26
x=13
Vậy x=13
Để \(5⋮\left(2a+3\right)\Leftrightarrow\left(2a+3\right)\inƯ\left(5\right)\)
\(\Leftrightarrow\left(2a+3\right)\in\left\{\pm1;\pm5\right\}\)
\(\Leftrightarrow a\in\left\{-1;-2;1;-4\right\}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) bằng 79/180
b)bằng 25/72 nha
k cho Jico nha
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a: \(\dfrac{5}{7}=\dfrac{5\cdot11}{7\cdot11}=\dfrac{55}{77}\)
\(\dfrac{9}{11}=\dfrac{9\cdot7}{11\cdot7}=\dfrac{63}{77}\)
b: \(\dfrac{36}{42}=\dfrac{6}{7}=\dfrac{6\cdot9}{7\cdot9}=\dfrac{54}{63}\)
\(-\dfrac{12}{54}=\dfrac{-2}{9}=\dfrac{-2\cdot7}{9\cdot7}=-\dfrac{14}{63}\)
c: \(\dfrac{-11}{30}=\dfrac{-11\cdot4}{30\cdot4}=\dfrac{-44}{120}\)
\(\dfrac{-17}{-40}=\dfrac{17}{40}=\dfrac{17\cdot3}{40\cdot3}=\dfrac{51}{120}\)
d: \(\dfrac{36}{42}=\dfrac{6}{7}=\dfrac{6\cdot3}{7\cdot3}=\dfrac{18}{21}\)
\(\dfrac{-12}{36}=\dfrac{-1}{3}=\dfrac{-1\cdot7}{3\cdot7}=\dfrac{-7}{21}\)
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1) \(\left|4-2x\right|.\dfrac{1}{3}=\dfrac{1}{3}\)
\(\left|4-2x\right|=\dfrac{1}{3}:\dfrac{1}{3}\)
\(\left|4-2x\right|=\dfrac{1}{3}.3\)
\(\left|4-2x\right|=1\)
=>\(4-2x=\pm1\)
+)\(TH1:4-2x=1\) +)\(TH2:4-2x=-1\)
\(2x=4-1\) \(2x=4-\left(-1\right)\)
\(2x=3\) \(2x=4+1\)
\(x=3:2\) \(2x=5\)
\(x=1,5\) \(x=5:2\)
Vậy x=1,5 \(x=2,5\)
Vậy x=2,5
2) \(\left(-3\right)^2:\left|x+\left(-1\right)\right|=-3\)
\(9:\left|x+\left(-1\right)\right|=-3\)
\(\left|x+\left(-1\right)\right|=9:\left(-3\right)\)
\(\left|x+\left(-1\right)\right|=-3\)
=> \(x+\left(-1\right)\) sẽ không có giá trị nào ( Vì giá trị tuyệt đối luôn luôn lớn hơn hoặc bằng 0 )
Vậy x = \(\varnothing\)
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g: \(=-457+237+23-123=-220-100=-320\)
h: \(=\left(1-3\right)+\left(5-7\right)+...+\left(41-43\right)+\left(45-47\right)\)
\(=\left(-2\right)+\left(-2\right)+...+\left(-2\right)+\left(-2\right)\)
\(=-2\cdot12=-24\)
i: \(=173+27-46-54-19=200-100-19=100-19=81\)
k: \(=-52+82+49-15+13-36\)
\(=30+34-23\)
=30+11
=41
l: \(=\left(3-5\right)+\left(7-9\right)+\left(11-13\right)+\left(15-17\right)\)
\(=\left(-2\right)+\left(-2\right)+\left(-2\right)+\left(-2\right)\)
=-8
m: \(=\left(1-2\right)+\left(3-4\right)+...+\left(2001-2002\right)+2003\)
\(=2003-1-1-...-1\)
\(=2003-1001=1002\)
n:Số số hạng là:
\(\left[\left(-51\right)-\left(-99\right)\right]:1+1=49\left(số\right)\)
Tổng là \(\left(-51-99\right)\cdot\dfrac{49}{2}=-3675\)
o: \(=-62-38+1523-2523-92\)
\(=-100+1000-92=900-92=808\)
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khi :
24 phút + 36 phút = 1 giờ
11 giờ + 13 giờ = 1 ngày
158 ngày + 207 ngày = 1 năm
46 năm + 54 năm = 1 thế kỉ
\(2x-\frac{7}{36}=\frac{11}{54}\)
\(2x=\frac{11}{54}+\frac{7}{36}\)
\(2x=\frac{43}{108}\)
\(x=\frac{43}{216}\)
2x - 7/36 = 11/54
= 2 * x - 7/36 = 11/54
= 2 * x = 11/54 + 7/36
= 2 * x = 43/108
x = 43/108 : 2
x = 43/216