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\(x+0,9=20,17\Leftrightarrow x=20,17-0,9=19,24\)
\(47,5-x=4,64\Leftrightarrow x=47,5-4,64=42,86\)
\(3x=\dfrac{5}{4}-\dfrac{1}{2}\Leftrightarrow3x=\dfrac{3}{4}\Leftrightarrow x=\dfrac{1}{4}\)
\(a.x=20,17-0,9=19,27\)
\(b.47,5-x=4,56\Leftrightarrow x=42,86\)
\(c.3.x=\dfrac{5}{4}-\dfrac{1}{2}\Leftrightarrow3x=\dfrac{3}{4}\Leftrightarrow x=\dfrac{1}{4}\)
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a) PT \(\Leftrightarrow x=\dfrac{6}{0,12}=50\)
Vậy \(x=50\)
b) PT \(\Leftrightarrow x=4\cdot2,5=10\)
Vậy \(x=10\)
c) PT \(\Leftrightarrow x=\dfrac{5,6}{4}=1,4\)
Vậy \(x=1,4\)
d) \(\Leftrightarrow x=\dfrac{\dfrac{2}{5}}{0,1}=4\)
Vậy \(x=4\)
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c] 7 * x + 8 * x + 9 * x + .... + 100 * x = 1025
(7+8+9+...+100)*x=1025
Coi A= 7+8+...+100
Số các số hạng của A là:
(100-7):1+1=94 (số)
=>A=(100+7)*94:2=5029
Ta lại có:
5029*x=1025
=>x=1025:5019=1025/5019
a, \(x.\left(\frac{3}{2}+\frac{1}{4}-\frac{1}{2}\right)=x.\left(\frac{6}{4}+\frac{1}{4}-\frac{2}{4}\right)=\frac{10}{9}\)
\(x.\frac{5}{4}=\frac{10}{9}\)
\(x=\frac{10}{9}:\frac{5}{4}=\frac{10}{9}.\frac{4}{5}=\frac{8}{9}\)
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c] 7 * x + 8 * x + 9 * x + .....+ 100 * x = 1025
=> x (7 + 8 + 9 +...+ 100) = 1025
=> x * 5029 = 1025
=> x = 1025/5029
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a) \(7.x+8.x+9.x+...+100.x=1025\)
\(\left(7+8+9+...+100\right).x=1025\)
\(5029.x=1025\)
\(x=1025\div5029\)
\(x=\frac{1025}{5029}\)
b) \(32.\left(x-3\right)+18.x=2\)
\(32.x-32.3+18.x=2\)
\(\left(32+18\right).x-96=2\)
\(50.x=98\)
\(x=98\div50\)
\(x=1,96\)
Chú ý nè: Dấu "." là dấu nhân đó!
a) 7.x+8.x+9.x+...+100.x=1025
(7+8+9+...+100).x=1025
5029.x=1025
x=1025÷5029
x=\(\frac{1025}{5029}\)
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X : 0,25 - X = 15,6
X × 4 - X = 15,6
X × (4 - 1) = 15,6
X × 3 = 15,6
X = 15,6 : 3
X = 5,2
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X : 0,1 - X : 4 - X × 3/4 = 2,25
X × 10 - X × 1/4 - X × 3/4 = 2,25
X × (10 - 1/4 - 3/4) = 2,25
X × 9 = 2,25
X = 2,25 : 9
X = 0,25
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a.
150 + x : 3 = 620 : 4
150 + x : 3 = 155
x : 3 = 155 - 150
x : 3 = 5
x = 5 x 3
x = 15
b.
x * 0,1 = 1/2 -2/5
x * 1/10 = 5/10 - 4/10
x * 1/10 = 1/10
x = 1/10 : 1/10
x = 1
c.
4/9 + 5/9 : x = 1
5/9 : x = 1 - 4/9
5/9 :x = 5/9
x = 5/9 : 5/9
x = 1
1) \(150+x.\frac{1}{3}=155\)
\(\frac{1}{3}x=5\)
\(x=15\)
2) \(x.\frac{1}{10}=\frac{1}{2}-\frac{2}{5}\)
\(\frac{1}{10}x=\frac{5}{10}-\frac{4}{10}\)
\(\frac{1}{10}x=\frac{1}{10}\)
\(x=1\)
3) \(\frac{4}{9}+\frac{9}{5}x=1\)
\(\frac{9}{5}x=\frac{9}{9}-\frac{4}{9}\)
\(\frac{9}{5}x=\frac{5}{9}\)
\(x=1\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\dfrac{1}{2}:3+x=1\dfrac{2}{3}\\ \Leftrightarrow x=\dfrac{5}{3}-\dfrac{1}{6}\\ \Leftrightarrow x=\dfrac{3}{2}\\2\dfrac{3}{4}-x=\dfrac{5}{6}+\dfrac{2}{3}\\ \Leftrightarrow x=\dfrac{11}{4}-\dfrac{5}{6}-\dfrac{2}{3} \\ \Leftrightarrow x=\dfrac{5}{4}\\ 5\dfrac{4}{10}-\dfrac{3}{4}\times x=\dfrac{2}{3}\\ \Leftrightarrow\dfrac{3}{4}x=\dfrac{54}{10}-\dfrac{2}{3}\\ \Leftrightarrow x=\dfrac{284}{45}\)
1) ....
1/2 : 3 = 5/3 - x
1/6 = 5/3 - x
x = 5/3 - 1/6 =3/2
2)....
11/4 - x = 3/2
x = 11/4 - 3/2 =5/4
3)...
27/5 - 3/4x = 2/3
3/4x = 27/5 - 2/3 =71/15
x = 71/15 : 3/4 =284/45
X:0,1+Xx3/4-Xx50%=1025
Xx10+Xx0,75+-Xx0,5=1025
Xx(10+0,75-0,5)=1025
X x 10,25=1025
X=1025:10,25
X=100
\(x\) : 0,1 + \(x\) x \(\dfrac{3}{4}\) - \(x\)x 50% = 1025
\(x\) x 10 + \(x\) x \(\dfrac{3}{4}\) - \(x\) x \(\dfrac{1}{2}\) = 1025
\(x\) x \(\left(10+\dfrac{3}{4}-\dfrac{1}{2}\right)\) = 1025
\(x\) x 10,25 = 1025
\(x\) = 1025 : 10,25
\(x\) = 100