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\(\dfrac{2x+19}{21}-\dfrac{2x+17}{23}=\dfrac{2x+7}{33}-\dfrac{2x+5}{35}\)
\(\Rightarrow\dfrac{2x+19}{21}-\dfrac{2x+17}{23}-\dfrac{2x+7}{33}+\dfrac{2x+5}{35}=0\)
\(\Rightarrow\left(\dfrac{2x+19}{21}+1\right)-\left(\dfrac{2x+17}{23}+1\right)-\left(\dfrac{2x+7}{33}+1\right)+\left(\dfrac{2x+5}{35}+1\right)=0\)
\(\Rightarrow\dfrac{2x+40}{21}-\dfrac{2x+40}{23}-\dfrac{2x+40}{33}+\dfrac{2x+40}{35}=0\)
\(\Rightarrow\left(2x+40\right)\left(\dfrac{1}{21}-\dfrac{1}{23}-\dfrac{1}{33}+\dfrac{1}{35}\right)=0\)
\(\Rightarrow2x+40=0\Rightarrow x=-20\)( do \(\dfrac{1}{21}-\dfrac{1}{23}-\dfrac{1}{33}+\dfrac{1}{35}>0\))
Ta có: \(\dfrac{2x+19}{21}-\dfrac{2x+17}{23}=\dfrac{2x+7}{33}-\dfrac{2x+5}{35}\)
\(\Leftrightarrow\left(2x+40\right)\left(\dfrac{1}{21}-\dfrac{1}{23}-\dfrac{1}{33}+\dfrac{1}{35}\right)=0\)
\(\Leftrightarrow2x+40=0\)
hay x=-20
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a,2x+5=19
2x = 19 - 5
2x = 14
x = 14 : 2
x = 7
b,
21+x+15=70
21 + x = 70 - 15
21 + x = 55
x = 55 - 21
x = 34
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A, 7x - x = 5^21 : 5^19 + 3 . 2^2 - 7^0
6x = 5^2 + 3 . 4 - 1
6x = 25 + 12 - 1
6x = 37 - 1
6x = 36
x = 6.
B, mình giải ra nhưng số to quá. Bạn thử kiểm tra lại đề xem.
C, 7x - 2x = 6^17 : 6^15 + 44 : 11
5x = 6^2 + 4
5x = 40
x = 8.
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Bài 1: Tìm x, biết
a )24-(36+5)=x b)14-21=(13-x)-(15+8)
24-41=x (13-x)-23=-7
x=-17 13-x=(-7)+23
Vậy x=-17 13-x=16
x=13-16
x=-3 Vậy x=-3
Bài 2:Tìm x, biết
a)17-x=-25+(-16+9) b)3x-21=-19-(-2x)
17-x=-25+(-7) 3x-21=-19+2x
17-x=-32 3x-2x=-19+21
x=17-(-32) x=4
x=49 Vậy x=4
Vậy x=49
Bài 1:
a. 24 - (36+5) = x
=> 24 - 41 = x
=> -17 = x
=> x = -17
b. 14 - 21 = (13 - x) - (15 + 8)
=> -7 = 13 - x - 23
=> -7 - 13 + 23 = -x
=> 3 = -x
=> x = -3
Bài 2:
a. 17 - x = -25 + (-16 + 9)
=> 17 - x = -25 + (-7)
=> 17 - x = -32
=> 17 + 32 = x
=> x = 49
b. 3x - 21 = -19 - (-2x)
=> 3x - 21 = -19 + 2x
=> 3x - 2x = -19 + 21
=> x = 2
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5/2+x=-3/5
x=-3/5-5/2
x=-31/10
vậy x=-31/10
-2x+5=23
-2x=23-5
-2x=18
x=18:-2
x=-9
vậy x=-9
Bài làm :
\(\frac{5}{2}+x=-3,5\)
\(\Leftrightarrow x=-3,5-\frac{5}{2}=-6\)
\(-2x+5=23\)
\(\Leftrightarrow-2x=18\)
\(\Leftrightarrow x=-9\)
\(\frac{x}{21}=\frac{2}{7}-\frac{4}{3}\)
\(\Leftrightarrow\frac{x}{21}=-\frac{22}{21}\)
\(\Leftrightarrow x=-22\)
\(\frac{5}{3}x-\frac{2}{5}x=\frac{19}{10}\)
\(\Leftrightarrow x\left(\frac{5}{3}-\frac{2}{5}\right)=\frac{19}{10}\)
\(\Leftrightarrow\frac{19}{15}x=\frac{19}{10}\)
\(\Leftrightarrow x=\frac{3}{2}\)
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