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= 7,3 x 82 + 7,3 x 14 + 7,3 x 4
= 7,3 x ( 82 + 14 + 4 )
= 7,3 x 100
= 730
1.7 x 0.25 +7.3 x 0.25 + 0.25
= 1.7 x \(\frac{1}{4}\)+ 7.3 x \(\frac{1}{4}\) + \(\frac{1}{4}\) x 1
= \(\frac{1}{4}\) x ( 1.7 + 7.3 + 1 )
= \(\frac{1}{4}\) x 10
= \(\frac{10}{4}=\frac{5}{2}\)
\(\frac{2x-4,36}{0,125}=0,25.42,9-11,7.0,25+0,25.0,8\)
\(\Leftrightarrow\frac{2x-4,36}{0,125}=0,25.\left(42,9-11.7+0,8\right)\)
\(\Leftrightarrow\frac{2x-4,36}{0,125}=0,25.32\)
\(\Leftrightarrow\frac{2x-4,36}{0,125}=8\)
\(\Leftrightarrow2x-4,36=1\)
\(\Leftrightarrow2x=5,36\)
\(\Leftrightarrow x=2,68\)
b) \(N=\frac{1}{1.5}+\frac{1}{5.10}+\frac{1}{10.15}+\frac{1}{15.20}+...+\frac{1}{2005.2010}\)
\(\Leftrightarrow N=\frac{1}{5}\left(1-\frac{1}{5}+\frac{1}{5}-\frac{1}{10}+\frac{1}{10}-\frac{1}{15}+\frac{1}{15}-\frac{1}{20}+...+\frac{1}{2005}-\frac{1}{2010}\right)\)
\(\Leftrightarrow N=\frac{1}{5}\left(1-\frac{1}{2010}\right)\)
\(\Leftrightarrow N=\frac{1}{5}.\frac{2009}{2010}=\frac{2009}{10050}\)
Bài 1:
a)\(\frac{2\cdot x-4,36}{0,125}=0,25\cdot42,9-11,7\cdot0,25+0,25\cdot0,8\)
\(\frac{2\cdot x-4,36}{0,125}=0,25\cdot\left(42,9-11,7+0,8\right)\)
\(\frac{2\cdot x-4,36}{0,125}=0,25\cdot32\)
\(\frac{2\cdot x-4,36}{0,125}=8\)
\(2\cdot x-4,36=8\cdot0,125\)
\(2\cdot x-4,36=1\)
\(2\cdot x=1+4,36\)
\(2\cdot x=5,36\)
\(x=\frac{5,36}{2}=2,68\)
b) \(N=\frac{1}{1\cdot5}+\frac{1}{5\cdot10}+\frac{1}{10\cdot15}+\frac{1}{15\cdot20}+...+\frac{1}{2005\cdot2010}\)
\(4N=\frac{4}{1\cdot5}+\frac{4}{5\cdot10}+\frac{4}{10\cdot15}+\frac{4}{15\cdot20}+...+\frac{4}{2005\cdot2010}\)
\(4N=1-\frac{1}{5}+\frac{1}{5}-\frac{1}{10}+\frac{1}{10}-\frac{1}{15}+\frac{1}{15}-\frac{1}{20}+...+\frac{1}{2005}-\frac{1}{2010}\)
\(4N=1-\frac{1}{2010}=\frac{2009}{2010}\)
\(N=\frac{2009}{2010}\div4=\frac{2009}{8040}\)
Bài 2:
a) ( x + 5,2 ) : 3,2 = 4,7 ( dư 0,5 )
\(x+5,2=4,7\cdot3,2+0,5\)
\(x+5,2=15,54\)
\(x=15,54-5,2=10,34\)
b)\(A=\frac{4047991-2010\cdot2009}{4050000-2011\cdot2009}\)
\(A=\frac{4047991-2010\cdot2009}{4050000-2009-2010\cdot2009}\)
\(A=\frac{4047991-2010\cdot2009}{4047991-2010\cdot2009}=1\)
Bài 3:
a) \(104,5\cdot x-14,1\cdot x+9,6\cdot x=25\)
\(x\cdot\left(104,5-14,1+9,6\right)=25\)
\(x\cdot100=25\)
\(x=\frac{25}{100}=\frac{1}{4}=0,25\)
b) \(T=\frac{2009\cdot2010+2000}{2011\cdot2010-2020}\)
\(T=\frac{2009\cdot2010+2000}{2009\cdot2010+4020-2020}\)
\(T=\frac{2009\cdot2010+2000}{2009\cdot2010+2000}=1\)
a) 7.3x8.3+3.8x7.3-5x7.3x0.4
=7.3x(8.3+3.8-5x0.4)
=7.3x10.1
=73.73
b)\(\frac{1}{10}:0.1-\frac{1}{8}:0.125+\frac{1}{2}:0.5-\frac{1}{4}:0.25\)
=1-1+1-1=0
c)\(\left(\frac{2727}{3636}+\frac{1212}{5454}\right)\times\left(\frac{9}{70}\right)=\left(\frac{3}{4}+\frac{2}{9}\right)\times\left(\frac{9}{70}\right)\)
=\(\frac{35}{36}\times\frac{9}{70}\)=\(\frac{1}{8}\)
d) 120x999+\(\frac{120}{5\times2.5\times125\times4\times0.8}\)
=120x999+\(\frac{120}{5000}\)
=120x999+\(\frac{3}{125}\)
=119880.024
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
= 5
a. 2,5 X16,27X4+7,3 b.0.25X1,25X8X4X0,5
= (2,5X4) X(7,3+16,27) = (0,25X4)X(0,5X8)X1,25
=10X23,57 =1X4X1,25
=235,7 =4X1,25
= 5
k cho mình nhé
Câu A = 13/2,8
Câu B = 0,9125
Câu C = 0,432
Câu D = 0,97
k mik nha
a. 7,3x2,5x0,8 b. 2,5x1,2x16
=7,3x(2,5x0,8) =(2,5x1,2)x16
=7,3x2 =3x16
=14,6 =48
a) 32,5 x 29,01 - 32,5 x 30 + 32,5 b) 12,9 x 0,5 - 17 x 0,25 - 3/4 + 11,1 : 2
= 32,5 x 29,01 - 32,5 x 30 + 32,5 x 1 = 12,9 x 2 x 0,25 - 17 x 0,25 - 0,75 + 5,55
= 32,5 x( 29,01 - 30 + 1) = 25,8 x 0,25 - 17 x 0,25 - 0,25 x 3 + 2,22 x 0,25
= 32,5 x 0,01 = 0,25 x ( 25,8 - 17 - 3 + 22,2 )
= 0,325 = 0,25 x 28 = 7
tk mk nha
#)Giải :
a) \(\frac{2xX-4,36}{0,125}=\)0,25 x 42,9 - 11,7 x 0,25 + 0,25 x 0,8
\(\frac{2xX-4,36}{0,125}=\)0,25 x ( 42,9 - 11,7 + 0,8 )
\(\frac{2xX-4,36}{0,125}=\)0,25 x 32
\(\frac{2xX-4,36}{0,125}=8\)
\(2xX-4,36=8x0,125\)
\(2xX-4,36=1\)
\(2xX=1+4,36\)
\(2xX=5,36\)
\(X=5,36:2\)
\(X=2,68\)
#~Will~be~Pens~#
a) 8,75 : 0,25 + 3,25 : 0,25
= 8,75 x 1/4 + 3,25 x 1/4
= 1/4 x (8,75 + 3,25)
= 1/4 x 12
= 3
b) 7,3 x 32,5 - 7,3 x 12,5
= 7,3 x (32,5 - 12,5)
= 7,3 x 20
=146
a: 8,75:0,25+3,25:0,25
=(8,75+3,25):0,25
=11x4
=44
b: 7,3x32,5-7,3x12,5
=7,3x(32,5-12,5)
=7,3x20=146