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a) 14,7 + (-8,4) + (-4,7) = (14,7 - 4,7) + (-8,4)
= 10 - 8,4 = 1,6
b) (-4,2).5,1 + 5,1.(-5,8) = 5,1. (- 4,2 - 5,8)
= 5,1. (-10) = -51
c) (-0,4: 0,04 + 10) . (1,2.20 + 12.8)
= (-10 + 10). (1,2.20 + 12.8)
= 0. (1,2.20 + 12.8) = 0.
\(\frac{12,48:0,5.6,25.4.2}{2.3,12.1,25:0,25.10}\)= \(\frac{12,48.2.6.25.4.2}{2.3,12.1,25.4.10}\)= \(\frac{3,12.4.2.1,25.5.4.2}{2.3,12.1,25.4.5.2}\)= \(4\)
A=1,25+2,75+4,25+........+17,75+19,25
A có ( 19,25 - 1,25 ) : 1,5 + 1 = 13 số hạng.
A = ( 19,25 + 1,25 ) . 13 : 2
A = 133,25
B = 5,8 . ( 168 - 100 ) + ( 4,5 + 1,3) . ( 15 + 26) + (7,3 - 1,5 )
B = 5,8 . 68 + 5,8 + 5,8
B = 5,8 ( 68 + 1 + 1 )
B = 5,8 . 70
B = 406
\(C=\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\frac{1}{56}\)
\(C=\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}\)
\(C=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}\)
\(C=\frac{1}{2}-\frac{1}{8}\)
\(C=\frac{3}{8}\)
\(\frac{-9}{2}+\left[\left(-5,8\right)-\left(-4,7\right)\right]\)
\(=\left(-4,5\right)+\left(-5,8\right)+4,7\)
\(=\left(-10,3\right)+4,7\)
\(=5,6\)
x.3,7+x.6,3=120b,x.3,7+x.6,3=120
x(3,7+6,3)=120x(3,7+6,3)=120
10x=12010x=120
x=120:10x=120:10
x=12(tm)
(15×24-x):0.25=100 : 1/4
(15×24-x):0.25 = 400
(15x24-x) = 100
360-x =100
x=260
(8.75+1.25 +5+1) x X=20
16 x X=20
X=20 :16
X=1.25
a) \(5.2^4+2.3^3-3,4\)
\(=5.2.2^3+2.3^3-3,4\)
\(=2.40+2.27-3,4\)
\(=2\left(40+37\right)-3,4\)
\(=2.77-4,3\)
\(=154-4,3=149,7\)
b) \(\dfrac{\dfrac{1}{3}-0,25+0,2}{1\dfrac{1}{6}-0,875+0,7}=\dfrac{2\left(\dfrac{1}{6}-0,125+\dfrac{1}{10}\right)}{7\left(\dfrac{1}{6}-0,125+\dfrac{1}{10}\right)}=\dfrac{2}{7}\)
a. \(5.2^4+2.3^3-3,4\)
\(=5.2^3.2+2.27-3,4\)
\(=2.\left(40+27\right)-3,4\)
\(=2.67-3,4\)
= 134 - 3,4 = 130,6
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 : \(x=\frac{69}{10}\)
c) 0,1+0,2-0,3-0,4+0,5+0,6-0,7-0,8+0,9+0,10
=(0,1+0,2-0,3-0,4)+(0,5+0,6-0,7-0,8)+(0,9+0,1)
=-0,4+(-0,4)+1
=-0,8+1
=-0,2
ok rồi nha
6,25 . 1,25 . 2,4 . 0,8
= (6,25 . 2,4) . (1,25 . 0,8)
= 15 . 1
= 15
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b,4,7 + (-3,4) + 5,19 + 3,4 + (-4,7)
= [ 4,7 + (-4,7)] + [(-3,4) + 3,4] + 5,19
= 0 + 0 + 5,19
= 5,19