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19 tháng 7 2021

Ta có:

\( \dfrac{7256.4375-725}{3650+4375.7255}\\ =\dfrac{7255.4375+4375-7255}{3650+4375.7255}\\ =\dfrac{7255.4375+\left(4375-725\right)}{3650+4375.7255}\\ =\dfrac{7255.4375+3650}{3650+4375.7255}\\ =1\)

   Vậy giá trị của  \(\dfrac{7256.4375-725}{3650+4375.7255}=1\)

19 tháng 7 2021

7256.4375-725=(7255+1).4375-725=7255.4375+4375-725=7255.4375+3650

⇒(7256.4375−725)/(3650+4375.7255)=(7255.4375+3650)/(3650+4375.7255)=1

a: \(=347\cdot4\cdot9\cdot400:8=347\cdot36\cdot50=624600\)

c: \(=16:\left\{400:\left[200-37-138\right]\right\}\)

\(=16:\left\{400:25\right\}=16:16=1\)

e: \(=46-\left[300:15\right]-2=46-20-2=24\)

15 tháng 12 2017

a) \(\frac{15}{12}+\frac{5}{13}-\frac{3}{12}-\frac{18}{13}\)

\(=\left(\frac{15}{12}-\frac{3}{12}\right)+\left(\frac{5}{13}-\frac{18}{13}\right)\)

\(=1+\left(-1\right)\)

\(=0\)

b) \(\frac{5^4.20^4}{25^5.4^5}=\frac{\left(20.5\right)^4}{\left(25.4\right)^5}=\frac{100^4}{100^5}=\frac{1}{100}\)

c) \(\frac{8^{10}+4^{10}}{8^4+4^{11}}=\frac{\left(2^3\right)^{10}+\left(2^2\right)^{10}}{\left(2^3\right)^4+\left(2^2\right)^{11}}=\frac{2^{30}+2^{20}}{2^{12}+2^{22}}=\frac{2^{12}.\left(2^{18}+2^8\right)}{2^{12}.\left(1+2^{10}\right)}=\frac{2^{18}+2^8}{1+2^{10}}=256\)

1 tháng 6 2017

C= \(\dfrac{1}{100}-\)(\(\dfrac{1}{1.2}\)+\(\dfrac{1}{2.3}\)+...+\(\dfrac{1}{98.99}\)+\(\dfrac{1}{99.100}\)

\(=\dfrac{1}{100}-\left(1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{98}-\dfrac{1}{99}+\dfrac{1}{99}-\dfrac{1}{100}\right)\)

=\(\dfrac{1}{100}-\left(1-\dfrac{1}{100}\right)\)

= \(\dfrac{1}{100}-\dfrac{99}{100}\)

=\(\dfrac{-98}{100}=-\dfrac{49}{50}\)

13 tháng 5 2017

Ta có:

\(=\dfrac{1}{100}-\dfrac{1}{100}+\dfrac{1}{99}-\dfrac{1}{99}+\dfrac{1}{98}-\dfrac{1}{98}+......+\dfrac{1}{3}-\dfrac{1}{3}+\dfrac{1}{2}-\dfrac{1}{2}+1\)

sau khi giản ước ta được như sau:

=\(\dfrac{1}{100}-1\)=\(\dfrac{-99}{100}\)

6 tháng 12 2017

\(\frac{\left(\frac{2}{3}\right)^3.\left(\frac{-3}{4}\right)^2.\left(-1\right)^5}{\left(\frac{2}{5}\right)^2.\left(\frac{-5}{12}\right)^3}=\frac{\frac{2^3}{3^3}.\frac{3^2}{4^2}.\left(-1\right)}{\frac{2^2}{5^2}.\frac{\left(-5\right)^3}{12^3}}=\)\(\frac{\frac{1}{6}.\left(-1\right)}{\frac{2^2}{5^2}.\frac{5^3}{2^6.3^3}.\left(-1\right)}=\frac{\frac{1}{2.3}}{\frac{5}{2^4.3^3}}=\frac{2^3.3^2}{5}=\frac{72}{5}\)

1 tháng 6 2017

A = \(\left(\dfrac{1}{3}+\dfrac{3}{5}+\dfrac{1}{15}\right)-\)\(\left(\dfrac{3}{4}+\dfrac{2}{9}+\dfrac{1}{36}\right)+\)\(\dfrac{1}{72}\)

= \(1-1+\dfrac{7}{12}\)

=\(\dfrac{1}{72}\)

6 tháng 7 2017

A = ( 1/3+3/5+1/15)-(3/4+2/9+1/36)+1/72

= 1-1+1/72

= 1/72

8 tháng 6 2017

\(P=\dfrac{0,75-0,6+\dfrac{3}{7}+\dfrac{3}{11}}{2,75-2,2+\dfrac{11}{7}+\dfrac{11}{13}}\)

\(P=\dfrac{3.\left(\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{7}+\dfrac{1}{13}\right)}{11.\left(\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{7}+\dfrac{1}{13}\right)}\)

\(P=\dfrac{3}{11}\)

9 tháng 6 2017

\(P=\dfrac{0,75-0,6+\dfrac{3}{7}+\dfrac{3}{13}}{2,75-2,2+\dfrac{11}{7}+\dfrac{11}{13}}=\dfrac{\dfrac{3}{4}-\dfrac{3}{5}+\dfrac{3}{7}+\dfrac{3}{13}}{\dfrac{11}{4}-\dfrac{11}{5}+\dfrac{11}{7}+\dfrac{11}{13}}\)

\(=\dfrac{3.\left(\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{7}+\dfrac{1}{13}\right)}{11.\left(\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{7}+\dfrac{1}{13}\right)}=\dfrac{3}{11}\)

18 tháng 5 2017

B=(\(\dfrac{1}{5}\)-\(\dfrac{1}{5}\))+(\(\dfrac{3}{7}\)-\(\dfrac{3}{7}\))+(\(\dfrac{5}{9}\)-\(\dfrac{5}{9}\))+(\(\dfrac{2}{11}\)-\(\dfrac{2}{11}\))+(\(\dfrac{7}{13}\)-\(\dfrac{7}{13}\))+\(\dfrac{9}{16}\)

B=\(\dfrac{9}{16}\)

21 tháng 5 2017

\(\dfrac{-9}{16}\) chứ