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a) \(\dfrac{1}{4}+\dfrac{\dfrac{3}{4}}{3x}=-5\)
\(\dfrac{\dfrac{3}{4}}{3x}=-5-\dfrac{1}{4}\)
\(\dfrac{\dfrac{3}{4}}{3x}=-\dfrac{21}{4}\)
\(3x=\dfrac{\dfrac{3}{4}}{-\dfrac{21}{4}}\)
\(3x=-\dfrac{1}{7}\)
\(x=\dfrac{-\dfrac{1}{7}}{3}\)
\(x=-\dfrac{1}{21}\)
a) 1/4 + 3/4 : 3x = -5
3/4 : 3x = -5 - 1/4
3/4 : 3x = -21/4
3x = 3/4: -21/4
3x = 1/-7
x = 1/-7 : 3
x = 1/-21
b) x - 25%x = 0,5
1.x - 1/4 . x = 1/2
(1 - 1/4) . x = 1/2
3/4 . x = 1/2
x = 1/2 : 3/4
x = 1/2 . 4/3
x = 2/3
[Giải:]
107 + ( 210 + x ) = 317
210 + x = 317 - 107
210 + x = 210
x = 210 - 210
x = 0
2x + (0,5 + 25%) = 0,75
2x + (0,5 + 0,25) = 0,75
2x + 0,75 = 0,75
2x = 0,75 - 0,75
2x = 0
x = 0 : 2
x = 0
4221 : (x - 16 ) = 21
x - 16 = 4221 : 21
x - 16 = 201
x = 201 + 16
x = 217
50% + 0,75x = 0,5
0,5 + 0,75x = 0,5
0,75x = 0,5 - 0,5
0,75x = 0
x = 0 : 0,75
x = 0
| - Câu khác làm tương tự - |
[ Hoq chắc ]
a, 107 + ( 210 - x ) = 317
210 - x = 317 - 107
210 - x = 210
x = 210 - 210
x = 0
Vậy x = 0
b, 2x + ( 0,5 + 25% ) = 0,75
2x + 0,75 = 0,75
2x = 0,75 - 0,75
2x = 0
x = 0
Vậy x = 0
c, 4221 : ( x - 16 ) = 21
x - 16 = 4221 : 21
x - 16 = 201
x = 201 + 16
x = 217
Vậy x = 217
d, 156 - ( x + 61 ) = 21
x + 61 = 156 - 21
x + 61 = 135
x = 135 - 61
x = 74
Vậy x = 74
e, ( 235 - x ) - 81 = 54
235 - x = 54 + 81
235 - x = 135
x = 235 - 135
x = 100
Vậy x = 100
f, 50% + 0,75. x = 0,5
0,75. x = 0,5 - 50%
0,75. x = 0
x = 0
Vậy x = 0
tìm x , biết :
a . 1,5 . x + 2,5 = 1
\(1,5.x=-1,5\)
\(x=\dfrac{-1,5}{1,5}\)
\(x=-1\)
b . ( 0,5 . x - 1,3 ) : 0,5 = -1,7
\(0,5.x-1,3=-0,85\)
\(0,5x=-2,15\)
\(x=\dfrac{-2,15}{0,5}\)
\(x=-4,3\)
c . 1,75 .x - 1,5 . x = 0,84
\(x\left(1,75-1,5\right)=0,84\)
\(x.0,25=0,84\)
\(x=3,36\)
d . x + 75% . x + 125% = 1
\(x+\dfrac{75}{100}.x+\dfrac{125}{100}=1\)
\(x+\dfrac{3}{4}.x+\dfrac{5}{4}=1\)
\(x+\dfrac{3}{4}.x=-\dfrac{1}{4}\)
\(x.\left(1+\dfrac{3}{4}\right)=-\dfrac{1}{4}\)
\(x.1,75=-\dfrac{1}{4}\)
\(x=-\dfrac{1}{7}\)
e . x - 25% .x + 75% = 1
\(x-\dfrac{25}{100}.x+\dfrac{75}{100}=1\)
\(x-\dfrac{1}{4}.x+\dfrac{3}{4}=1\)
\(x-\dfrac{1}{4}.x=\dfrac{1}{4}\)
\(x.\left(1-\dfrac{1}{4}\right)=\dfrac{1}{4}\)
\(x.\dfrac{3}{4}=\dfrac{1}{4}\)
\(x=\dfrac{1}{3}\)
f . | x - 1,5 | = 2,37
TH1 : \(x-1,5=2,37\)
\(x=2,37+1,5\)
\(x=3,87\)
TH2 : \(x-1,5=-2,37\)
\(x=-2,37+1,5\)
\(x=-0,87\)
a) 0,5 x - \(\frac{2}{3}\)x = \(\frac{7}{12}\)
x . ( 0,5 - \(\frac{2}{3}\)) = \(\frac{7}{12}\)
x . \(\frac{-1}{6}\) = \(\frac{7}{12}\)
x = \(\frac{7}{12}\): \(\frac{-1}{6}\)
x = \(\frac{-7}{2}\)
b) x : \(\frac{25}{3}\) = -25
x = -25 . \(\frac{25}{3}\)
x = \(\frac{-625}{3}\)
c) 5,5 x = \(\frac{13}{15}\)
x = \(\frac{13}{15}\): 5,5
x = \(\frac{26}{165}\)
d) (\(\frac{3x}{7}\)+ 1 ) : ( -4) = \(\frac{-1}{28}\)
( \(\frac{3x}{7}\)+ 1 ) = \(\frac{-1}{28}\). ( -4)
\(\frac{3x}{7}\)+ 1 = \(\frac{1}{7}\)
\(\frac{3x}{7}\) = \(\frac{1}{7}\)- 1
\(\frac{3x}{7}\) = \(\frac{-6}{7}\)
=> x = -2
e) y + 30% y = -1,3
y + \(\frac{3}{10}\)y = -1,3
y . ( 1 + \(\frac{3}{10}\)) = -1,3
y . \(\frac{13}{10}\) = -1,3
y = -1,3 : \(\frac{13}{10}\)
y = -1
g) y - 25% y = \(\frac{1}{2}\)
y - \(\frac{1}{4}\)y = \(\frac{1}{2}\)
y . ( 1 - \(\frac{1}{4}\)) = \(\frac{1}{2}\)
y . \(\frac{3}{4}\) = \(\frac{1}{2}\)
y = \(\frac{1}{2}\): \(\frac{3}{4}\)
y = \(\frac{2}{3}\)
ai tốt bụng thì tk cho mk nha, mk đg âm điểm đây huhu
x-1/4.x=1/2
1.x-1/4.x
x.(1-1/4)=1/2
x.3/4=1/2
x=1/2:3/4
x=2/3
x - 25%.x = 0,5
x - 1/4x = 0,5
x.4 - 1/4x.4 = 0,5.4
4x - x = 2
3x = 2
x = 2/3
=> x = 2/3
1. Tìm x, biết:
a) x + 30% x = -39
=>x + (-9) = -39
=> x = -39 - (-9)
=> x = -30
b) x +25% = -0,5
=> x + 0,25= -0,5
=> x = -0,5 - 0,25
=> x = \(-\frac{3}{4}\) = -0,75
\(a) \frac{4}{5}.x=\frac{8}{35}\)
\(\implies x= \frac{8}{35}:\frac{4}{5}\)
\(\implies x=\frac{8}{35}.\frac{5}{4}\)
\(\implies x=\frac{2}{7}\). Vậy \(x=\frac{2}{7}\)
\(b) \frac{3}{5}x-\frac{1}{2}=\frac{1}{7}\)
\(\implies \frac{3}{5}x=\frac{1}{7}+\frac{1}{2}\)
\(\implies \frac{3}{5}x=\frac{9}{14}\)
\(\implies x=\frac{9}{14}:\frac{3}{5}\)
\(\implies x=\frac{9}{14}.\frac{5}{3} \)
\(\implies x=\frac{15}{14}\). Vậy \(x=\frac{15}{14}\)
\(c) x-25\% x=0,5\)
\(\implies 75\% x=0,5\)
\(\implies \frac{3}{4}x=\frac{1}{2}\)
\(\implies x=\frac{1}{2}:\frac{3}{4}\)
\(\implies x=\frac{1}{2}.\frac{4}{3}\)
\(\implies x=\frac{2}{3}\). Vậy \(x=\frac{2}{3}\)
\(d) (\frac{1}{24.25}+\frac{1}{25.26}+...+\frac{1}{29.30}).120+x:\frac{1}{3}=-4\)
Có: \(\frac{1}{24.25}+\frac{1}{25.26}+...+\frac{1}{29.30}\)
\(=\frac{1}{24}-\frac{1}{25}+\frac{1}{25}-\frac{1}{26}+...+\frac{1}{29}-\frac{1}{30}\)
\(=\frac{1}{24}-\frac{1}{30}\)
\(=\frac{1}{120}\)
Thay vào ta có: \(\frac{1}{120}.120+x:\frac{1}{3}=-4\)
\(\implies 1+x:\frac{1}{3}=-4\)
\(\implies x:\frac{1}{3}=-5\)
\(\implies x=-5.\frac{1}{3}\)
\(\implies x=\frac{-5}{3}\). Vậy \(x=\frac{-5}{3}\)
~ Hok tốt a~
\(\frac{4}{5}.x=\frac{8}{35}\) \(\frac{3}{5}x-\frac{1}{2}=\frac{1}{7}\)
\(x=\frac{8}{35}:\frac{4}{5}\) \(\frac{3}{5}x=\frac{1}{7}+\frac{1}{2}\)
\(x=\frac{8}{35}.\frac{5}{4}\) \(\frac{3}{5}x=\frac{9}{14}\)
\(x=\frac{2}{7}\) \(x=\frac{9}{14}:\frac{3}{5}\)
Vậy \(x=\frac{2}{7}\) \(x=\frac{9}{14}.\frac{5}{3}\)
\(x-25\%x=0.5\) \(x=\frac{15}{14}\)
\(x-\frac{1}{4}x=\frac{1}{2}\) Vậy \(x=\frac{15}{14}\)
\(x\left(1-\frac{1}{4}\right)=\frac{1}{2}\) \(\left(\frac{1}{24.25}+\frac{1}{25.26}+...+\frac{1}{29.30}\right).120+x:\frac{1}{3}=-4\)
\(x=\frac{1}{2}:\frac{3}{4}\) \(\left(\frac{1}{24}-\frac{1}{25}+\frac{1}{25}-\frac{1}{26}+...+\frac{1}{29}-\frac{1}{30}\right).120+x:\frac{1}{3}=-4\) \(x=\frac{2}{3}\) \(\left(\frac{1}{24}-\frac{1}{30}\right).120+x:\frac{1}{3}=-4\)
Vậy \(x=\frac{2}{3}\) \(\frac{1}{120}.120+x:\frac{1}{3}=-4\)
\(1+x:\frac{1}{3}=-4\)
\(x:\frac{1}{3}=\left(-4\right)-1\)
\(x:\frac{1}{3}=-5\)
\(x=\left(-5\right).\frac{1}{3}\)
\(x=-\frac{5}{3}\)
Vậy \(x=-\frac{5}{3}\)
......................?
mik ko biết
mong bn thông cảm
nha ................
\(x-25\%.x=0,5\)
\(\Rightarrow\)\(x-\frac{1}{4}x=\frac{1}{2}\)
\(\Rightarrow\)\(x\left(1-\frac{1}{4}\right)=\frac{1}{2}\)
\(\Rightarrow\)\(\frac{3}{4}x=\frac{1}{2}\)
\(\Rightarrow\)\(x=\frac{2}{3}\)