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a, \(\left(x-158\right):6=20\)
\(x-158=20.6\)
\(x-158=120\)
\(x=120+158\)
\(x=278\)
~~~Hok tốt~~~
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 : \(x=\frac{69}{10}\)
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)
x - 0,25 = 43/4 + 18/5
\(x-\frac{1}{4}=\frac{287}{20}\)
\(x=\frac{287}{20}+\frac{1}{4}\)
\(x=\frac{73}{5}\)
\(x-0,25=\frac{43}{4}+\frac{18}{5}\)
\(\Rightarrow x-\frac{1}{4}=\frac{43}{4}+\frac{18}{5}\)
\(\Rightarrow x-\frac{1}{4}=\frac{287}{20}\)
\(\Rightarrow x=\frac{287}{20}+\frac{1}{4}\)
\(\Rightarrow x=\frac{73}{5}\)
\(\Rightarrow x=14,6\)
a, (10/3:x).(-5/4)=-10/3
10/3:x=-10/3:(-5/4)
10/3:x=8/3
x=10/3:8/3
x=5/4
b,(-6/5+x):(-18/5)=-1/4
-6/5+x=-1/4.(-18/5)
-6/5+x=9/10
x=9/10-(-6/5)=9/10+6/5
x=21/10
c,-22/15.x+1/3=-2/5
-22/15.x=-2/5-1/3=-11/15
x=-11/15:(-22/15)
x=11/21
d,(0,25-30%x).1/3=-31/6+1/4=-59/12
1/4-3/10x=-59/12:1/3=-59/4
3/10x=1/4-(-59/4)=1/4+59/4=15
x=15:3/10
x=50
e,(0,5x-3/7):1/2=8/7
1/2x=8/7.1/2=4/7
x=4/7:1/2
x=8/7
a, 2,5 x 16,27 x 4 + 7,3
\(=\left(2,5\times4\right)\times16,27+7,3\)
\(=10\times16,27+7,3\)
\(=162,7+7,3\)
\(=170\)
b, 0,25 x 1,25 x 8 x 4 x 0,5
\(=\left(0,25\times4\right)\times\left(1,25\times8\right)\times0,5\)
\(=1\times10\times0,5\)
\(=5\)
c, 500 x 3,26 x 0,02 : 0,5
\(=\left(500\times0,02\right)\times3,26\div0,5\)
\(=10\times3,26\times\frac{10}{5}\)
\(=3,26\times20\)
\(=65,2\)
d, 32,4 x 6,24 + 3,66 x 32,4 + 0,5
\(=32.4\times\left(3,66+6,24\right)+0,5\)
\(=32,4\times9,9+0,5\)
\(=320,76+0,5\)
\(=321,26\)
e, 17,2 x 9,55 + 9,45 x 17,2 + 17,2
cố gắng tìm nhân tử chung hay nhóm làm sao ra dcd số tròn chục hay trăm j đó là xong rồi
a) 2,5 x 16,27 x 4 + 7,3
= 2,5 x 4 x 16,27 + 7,3
= 10 x 16,27 + 7,3
= 162,7 + 7,3
= 170
b) 0,25 x 1,25 x 8 x 4 x 0,5
= (0,25 x 4) x (1,25 x 8) x 0,5
= 1 x 10 x 0,5
= 10 x 0,5
= 5
c) 500 x 3,26 x 0,02 : 0,5
= 500 x 3,26 x 0,02 x 2
= (500 x 2 x 0,02) x 3,26
= 20 x 3,26
= 2 x 3,26 x 10
= 6,52 x 10
= 65,2
d) 32,4 x 6,24 + 3,66 x 32,4 + 0,5
= 32,4 x (6,24 + 3,66) + 0,5
= 32,4 x 9,9 + 0,5
= 320,76 + 0,5
= 321,26
d) 17,2 x 9,55 + 9,45 x 17,2 + 17,2
= 17,2 x (9,55 + 9,45 + 1)
= 17,2 x 20
= 17,2 x 10 x 2
= 172 x 2
= 344
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.
\(x-0,25=\frac{43}{4}-\frac{18}{5}\)
\(x-\frac{1}{4}=\frac{43}{4}-\frac{18}{5}\)
\(x=\frac{43}{4}-\frac{18}{5}+\frac{1}{4}\)
\(x=\left(\frac{43}{4}+\frac{1}{4}\right)-\frac{18}{5}\)
\(x=\frac{44}{4}-\frac{18}{5}\)
\(x=11-\frac{18}{5}\)
\(x=\frac{37}{5}\)
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