\(\frac{1}{3}x+\frac{3}{4}x-75\%=-5\frac{1}{4}\)

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18 tháng 4 2019

1/3x + 3/4x - 75% = -5 1/4

=> x - 3/4 = -21/4

=> x = -21/4 + 3/4

=> x = -9/2

60%x + 5/6x = -76

=> 3/5x + 5/6x = -76

=> 43/30x = -76

=> x = -76 : 43/30

=> x = -2280/43

18 tháng 4 2019

\(\frac{1}{3}x+\frac{3}{4}x-75\%=-5\frac{1}{4}\)

\(\frac{13}{12}x-\frac{3}{4}=-\frac{21}{4}\)

\(\frac{13}{12}x=-\frac{9}{2}\)

\(x=-\frac{54}{13}\)

\(60\%.x+\frac{2}{3}x=-76\)

\(\frac{3}{5}x+\frac{2}{3}x=-76\)

\(\frac{19}{15}x=-76\)

\(x=-60\)

Bài 2: 

b: x+25%x=-1,25

=>1,25x=-1,25

hay x=-1

c: x-75%x=1/4

=>1/4x=1/4

hay x=1

Bài 2: 

a: =3/2-11/4=6/4-11/4=-5/4

b: =-49/6-17/2=-49/6-51/6=-100/6=-50/3

15 tháng 7 2015

A)\(75\%.x-\frac{3}{2}:\frac{5}{4}=3\frac{1}{2}+25\%\)

<=>\(\frac{3}{4}x-\frac{6}{5}=\frac{7}{2}+\frac{1}{4}\)

<=>\(\frac{3}{4}x=\frac{7}{2}+\frac{1}{4}+\frac{6}{5}\)

<=>\(\frac{3}{4}x=\frac{99}{20}\)

<=>\(x=\frac{33}{5}\)

 

B)\(\left(x-\frac{3}{4}\right).50\%-\frac{2}{7}=1+\frac{3}{4}\)

<=>\(\left(x-\frac{3}{4}\right)\cdot\frac{1}{2}=\frac{7}{4}\)

<=>\(\frac{1}{2}x-\frac{3}{8}=\frac{7}{4}\)

<=>\(\frac{1}{2}x=\frac{17}{8}\)

<=>\(x=\frac{17}{4}\)

C)\(\left(\frac{5}{6}-2\frac{1}{2}\right):x=\frac{2}{5}-\frac{1}{3}\)

<=>\(-\frac{5}{3}:x=\frac{1}{15}\)

<=>\(x=-\frac{25}{3}\)

 

D)\(\left(\frac{1}{4}-x\right)-\frac{1}{2}=2\frac{1}{2}+1\)

<=>\(\frac{1}{4}-x-\frac{1}{2}=\frac{7}{2}\)

<=>\(-\frac{1}{4}-x=\frac{7}{2}\)

<=>\(x=-\frac{15}{4}\)

16 tháng 8 2017

x=-2^(3/2)/căn bậc hai(5), x=2^(3/2)/căn bậc hai(5)

14 tháng 4 2019

\(2.THPT\)

\(A=\frac{9}{1.2}+\frac{9}{2.3}+\frac{9}{3.4}+...+\frac{9}{98.99}+\frac{9}{99.100}\)

\(A=9\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{99.100}\right)\)

\(A=9\left(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{99}-\frac{1}{100}\right)\)

\(A=9\left(1-\frac{1}{100}\right)\)

\(A=9.\frac{99}{100}\)

\(A=\frac{891}{100}\)

\(B=\frac{2}{5.7}+\frac{2}{7.9}+\frac{2}{9.11}+...+\frac{2}{93.95}\)

\(B=\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}+...+\frac{1}{93}-\frac{1}{95}\)

\(B=\frac{1}{5}-\frac{1}{95}\)

\(B=\frac{18}{95}\)

\(D=\frac{5}{2.7}+\frac{4}{7.11}+\frac{3}{11.14}+\frac{1}{14.15}+\frac{13}{15.28}\)

\(D=\frac{1}{2}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+\frac{1}{14}-\frac{1}{15}+\frac{1}{15}-\frac{1}{28}\)

\(D=\frac{1}{2}-\frac{1}{28}\)

\(D=\frac{13}{28}\)