-4 . (-3 . 15) . 2,5 - 1,25 . (-4,1) . 8 + 0,2

= -4 . (-45) . 2,5 - (-5,125) . 8 + 0,2

= 180 . 2,5 - (-41) + 0,2

= 450 + 41 + 0,2

= 491,2

sai thì thôi nha!

A.   7,01 x 4 x 25

     = 7,01 x ( 4 x 25 )

    = 7,01 x 100

    = 701

B.   5 x 250 x 0,2

  = (5 x 0,2) x 250

  = 1 x 250

  =  250

C.   1,25 x 0,29 x 8

= (1,25 x 8 ) x 0,29

= 10 x 0,29

= 2,9

D.   0,04 x 0,1 x 25

= ( 0,04 x 25 ) x 0,1

= 1 x 0,1

=  0,1

a) 0,03

b) 3

c) 1,7

d) 1

1)

a)0,03

b)3

c)1,7

d)1

\(\frac{0,8\times0,4\times1,25\times2,5\times31,8+68,2}{0,1\times12,5\times4\times2,5\times2\times8\times0,2\times5}\)

\(=\frac{\left(0,8\times1,25\right)\times\left(0,4\times2,5\right)\times31,8+68,2}{0,1\times\left(12,5\times8\right)\times\left(4\times2,5\right)\times2\times\left(0,2\times5\right)}\)

\(=\frac{1\times1\times31,8+68,2}{0,1\times100\times10\times2\times1}\)

\(=\frac{31,8+68,2}{0,1\times100\times10\times2\times1}=\frac{100}{200}=\frac{1}{2}\)

a: \(=\left(1.25\right)^{16}\cdot8^{16}\cdot8=8\cdot10^{16}\)

b: \(=\left(\dfrac{5}{2}\right)^{13}\cdot4^{13}\cdot4^2=10^{13}\cdot4^2\)

c: \(=\left(0.25\right)^4\cdot8^4\cdot8^2=2^4\cdot8^2=64\cdot16=1024\)

d: \(=\left(\dfrac{1}{2}\right)^{15}\cdot2^{18}=2^3=8\)

e: \(=\left(\dfrac{1}{3}\cdot6\right)^7\cdot\left(\dfrac{1}{2}\right)^7\cdot\dfrac{1}{2}=2^7\cdot\left(\dfrac{1}{2}\right)^7\cdot\dfrac{1}{2}=\dfrac{1}{2}\)

a: \(=\left(1.25\right)^{16}\cdot8^{16}\cdot8=8\)

b: \(=\left(2.5\right)^9\cdot4^9\cdot4^6=4^6\cdot10^9\)

4/5 - (-2/7) - 7/10

= 4/5 + 2/7 - 7/10

= 8/10 - 7/10 + 2/7

= 1/10 + 2/7

= 7/70 + 20/70

= 27/70

\(\dfrac{4}{5}-\left(-\dfrac{2}{7}\right)-\dfrac{7}{10}\)

\(=\dfrac{4}{5}+\dfrac{2}{7}-\dfrac{7}{10}\)

\(=\dfrac{8-7}{10}+\dfrac{2}{7}\)

\(=\dfrac{1}{10}+\dfrac{2}{7}\)

\(=\dfrac{7+20}{70}\)

\(=\dfrac{27}{70}\)

a, \(2,5:4x=0,5:0,2\)

\(\Rightarrow4x=\dfrac{2,5.0,2}{0,5}\)

\(\Rightarrow4x=1\Rightarrow x=\dfrac{1}{4}\)

b, \(\dfrac{1}{5}x:3=\dfrac{2}{3}:0,5\)

\(\Rightarrow\dfrac{1}{5}x=\dfrac{3.\dfrac{2}{3}}{0,5}\)

\(\Rightarrow\dfrac{1}{5}x=4\Rightarrow x=20\)

c, \(1,25:0,8=\dfrac{3}{8}:0,2x\)

\(\Rightarrow0,2x=\dfrac{0,8.\dfrac{3}{8}}{1,25}\)

\(\Rightarrow0,2x=0,24\Rightarrow x=1,2\)

Chúc bạn học tốt!!

a, \(2,5:4x=0,5:0,2\)

\(2,5:4x=2,5\)

\(4x=2,5:2,5\)

\(4x=1\)

\(x=1:4\)

\(x=\dfrac{1}{4}\)

Vậy .............

b, \(\dfrac{1}{5}x:3=\dfrac{2}{3}\)

\(\dfrac{1}{5}x=\dfrac{2}{3}.3\)

\(\dfrac{1}{5}x=2\)

\(x=2:\dfrac{1}{5}\)

\(x=10\)

Vậy .....

c, \(1,25:0,8=\dfrac{3}{8}:0,2x\)

\(1,5625=\dfrac{3}{8}:0,2x\)

\(0,2x=\dfrac{3}{8}:1,5625\)

\(0,2x=0,24\)

\(x=0,24:0,2\)

\(x=1,2\)

Vậy ...