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9 tháng 8 2015
\(\frac{12,48:0,5.6,25.4.2}{2.3,12.1,25:0,25.10}\)= \(\frac{12,48.2.6.25.4.2}{2.3,12.1,25.4.10}\)= \(\frac{3,12.4.2.1,25.5.4.2}{2.3,12.1,25.4.5.2}\)= \(4\)
KL
1
H9
HT.Phong (9A5)
CTVHS
19 tháng 8 2023
\(\left(84,6-2\cdot x\right):3,02=5,1\)
\(\Rightarrow84,6-2\cdot x=15,402\)
\(\Rightarrow2\cdot x=69,198\)
\(\Rightarrow x=69,198:2\)
\(\Rightarrow x=34,599\)
_____________
\(\left(15\cdot24-x\right):0,25=100:0,25\)
\(\Rightarrow\left(360-x\right):0,25=400\)
\(\Rightarrow360-x=100\)
\(\Rightarrow x-360-100\)
\(\Rightarrow x=260\)
______________
\(128\cdot x-12\cdot x-16\cdot x=5200\)
\(\Rightarrow x\cdot\left(128-12-16\right)=5200\)
\(\Rightarrow x\cdot100=5200\)
\(\Rightarrow x=5200:100\)
\(\Rightarrow x=52\)
__________________
\(5\cdot x+3,75\cdot x+1,25\cdot x=20\)
\(\Rightarrow x\cdot\left(5+3,75+1,25\right)=20\)
\(\Rightarrow10\cdot x=20\)
\(\Rightarrow x=20:10\)
\(\Rightarrow x=2\)
H9
HT.Phong (9A5)
CTVHS
19 tháng 8 2023
\(x\cdot3,7+x\cdot6,3=360:120\)
\(\Rightarrow x\cdot\left(3,7+6,3\right)=3\)
\(\Rightarrow x\cdot10=3\)
\(\Rightarrow x=\dfrac{3}{10}\)
__________________
\(x\cdot23-6\cdot23+x\cdot69=320\)
\(\Rightarrow x\cdot\left(23+69\right)=320+6\cdot23\)
\(\Rightarrow x\cdot92=458\)
\(\Rightarrow x=458:92\)
\(\Rightarrow x=\dfrac{229}{46}\)
___________________
\(\left(x+1\right)\left(x+2\right)=72\)
\(\Rightarrow x^2+2x+x+2=72\)
\(\Rightarrow x^2+3x+2=72\)
\(\Rightarrow x^2+3x+2-72=0\)
\(\Rightarrow x^2+3x-70=0\)
\(\Rightarrow x^2+10x-7x-70=0\)
\(\Rightarrow\left(x-7\right)\left(x+10\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=7\\x=-10\end{matrix}\right.\)
___________________
\(\left(x+2\right)\cdot16\cdot x=160x\)
\(\Rightarrow16x^2+32x=160x\)
\(\Rightarrow16x^2+32x-160x=0\)
\(\Rightarrow16x^2-128x=0\)
\(\Rightarrow16x\left(x-8\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=8\end{matrix}\right.\)
DT
5
DH
8 tháng 8 2019
a, \(\left(x-158\right):6=20\)
\(x-158=20.6\)
\(x-158=120\)
\(x=120+158\)
\(x=278\)
~~~Hok tốt~~~
8 tháng 8 2019
a) \(\left(x-158\right):6=20\)
\(\Leftrightarrow x-158=\frac{20}{6}=\frac{10}{3}\)
\(\Leftrightarrow x=\frac{10}{3}+158\)
\(\Leftrightarrow x=\frac{484}{3}\)
Vậy : \(x=\frac{484}{3}\)
b) \(x-1,25.4=2,5\)
\(\Leftrightarrow x-5=2,5\)
\(\Leftrightarrow x=2,5+5\)
\(\Leftrightarrow x=7,5\)
Vậy : \(x=7,5\)
c) \(x+0,25=\frac{43}{4}-\frac{18}{5}\)
\(\Leftrightarrow x+\frac{1}{4}=\frac{143}{20}\)
\(\Leftrightarrow x=\frac{143}{20}-\frac{1}{4}\)
\(\Leftrightarrow x=\frac{69}{10}\)
Vậy : \(x=\frac{69}{10}\)
PU
1
5 tháng 7 2018
\(\dfrac{x}{2}+\dfrac{1,25}{0,25}=\dfrac{3,45}{0,2}\)
\(\Rightarrow\dfrac{x}{2}=\dfrac{3,45}{0,2}-\dfrac{1,25}{0,25}=\dfrac{49}{4}\)
\(\Rightarrow x=\dfrac{49.2}{4}=\dfrac{49}{2}\)
Vậy : .............
SL
2
PA
15 tháng 7 2016
a.
\(1,25\times4-x=2,5\)
\(5-x=2,5\)
\(x=5-2,5\)
\(x=2,5\)
b.
\(\left(158-x\right)\div7=20\)
\(158-x=20\times7\)
\(158-x=140\)
\(x=158-140\)
\(x=18\)
c.
\(x-0,25=\frac{43}{4}-\frac{18}{5}\)
\(x-\frac{1}{4}=\frac{43}{4}-\frac{18}{5}\)
\(x=\frac{43}{4}-\frac{18}{5}+\frac{1}{4}\)
\(x=\left(\frac{43}{4}+\frac{1}{4}\right)-\frac{18}{5}\)
\(x=\frac{44}{4}-\frac{18}{5}\)
\(x=11-\frac{18}{5}\)
\(x=\frac{37}{5}\)
15 tháng 7 2016
a. 1,25 × 4 - x = 2,5
5- x= 2,5
x= 5-2,5
x=2,5
b.(158- x) :7= 20
158- x= 20x7
158 -x= 140
x=158- 140
x=18
c. x- 0,25= \(\frac{43}{4}+\frac{18}{5}\)
x- 0,25=14,35
x= 14,35+ 0,25
x=14,6
HT
4 tháng 8 2017
a) \(\left(\frac{2x}{5}-1\right):\left(-5\right)=\frac{1}{7}\)
\(\frac{2x}{5}-1=\frac{1}{7}.\left(-5\right)\)
\(\frac{2x}{5}-1=\frac{-5}{7}\)
\(\frac{2x}{5}=\frac{-5}{7}+\frac{7}{7}\)
\(\frac{2x}{5}=\frac{2}{7}\)
\(=>2x.7=2.5\)
\(=>14x=10\)
\(=>x=\frac{5}{7}\)
c) \(\left|3,5+2,5x\right|-2,5=3,5\)
\(\left|3,5+2,5x\right|=3,5+2,5\)
\(\left|3,5+2,5x\right|=6\)
\(TH1\) \(3,5+2,5x=6\) \(TH2\) \(3,5+2,5x=-6\)
\(2,5x=6-3,5\) \(2,5x=-6-3,5\)
\(2,5x=2,5\) \(2,5x=-9.5\)
\(x=1\) \(x=-3,8\)
vậy \(x=1\) hoặc \(x=-3,8\)
câu d) làm tương tự như câu c)
2x3,12x1,25x0,25x10=2x3,12x(1,25:0,25x10)
=2x3,12 x50
=100x3,12=312