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#)Giải :
\(\left(92-\frac{1}{9}-\frac{2}{10}-\frac{3}{10}-...-\frac{92}{100}\right):\left(\frac{1}{45}+\frac{1}{50}+\frac{1}{55}+...+\frac{1}{500}\right)\)
\(=\left(1-\frac{1}{9}+1-\frac{2}{10}+1-\frac{3}{11}+...+1-\frac{92}{100}\right)\div\frac{1}{5}\times\left(\frac{1}{9}+\frac{1}{10}+\frac{1}{11}+...+\frac{1}{100}\right)\)
\(=\left(\frac{8}{9}+\frac{8}{10}+\frac{8}{11}+...+\frac{8}{100}\right)\div\frac{1}{5}\times\left(\frac{1}{9}+\frac{1}{10}+\frac{1}{11}+...+\frac{1}{100}\right)\)
\(=8\times\left(\frac{1}{9}+\frac{1}{10}+\frac{1}{11}+...+\frac{1}{100}\right)\div\frac{1}{5}\times\left(\frac{1}{9}+\frac{1}{10}+\frac{1}{11}+...+\frac{1}{100}\right)\)
\(=8\div\frac{1}{5}\)
\(=40\)
#~Will~be~Pens~#
x : 100 + 0.99 x x = 0.5
x x 0.01 + 0.99 x x = 0.5
x x ( 0.01 + 0.99 ) = 0.5
x x 1 = 0.5 x 1
x = 0.5
x + ( x + 1 ) + ( x + 2 ) + ( x + 3 ) + ( x + 4 ) + ... + ( x + 100 ) = 11 000
<=> ( x + x + x + x + x + ... + x ) + ( 1 + 2 + 3 + 4 + ... + 100 ) = 11 000
<=> 101x + \(\frac{\left(100+1\right)\left[\left(100-1\right):1+1\right]}{2}\)= 11 000 ( vì sao em để 101x thì idol biết mà :33 )
<=> 101x + 5050 = 11 000
<=> 101x = 5950
<=> x = 5950/101
c) (x+1) + (x+2) + ... + (x+5) = 90
=> 5x + ( 1 + 2 + ... + 5 ) = 90
5x + 15 = 90
5x = 90 - 15
5x = 75
x = 75 : 5
x = 15
d) (x+1) + (x+2) + .... + (x+100) = 20150
=> 100x + ( 1+2+...+100 ) = 20150
100x + 5050 = 20150
100x = 20150 - 5050
100x = 15100
x = 15100 : 100
x = 151
Ta có : (x + 1) + (x + 2) + (x + 3) + (x + 4) + (x + 5) = 90
<=> x + x + x+ x + x + (1 + 2 + 3 + 4 + 5) = 90
<=> 5x + 15 = 90
=> 5x = 75
=> x = 15
\(\left(1-\frac{3}{4}\right).\left(1-\frac{3}{7}\right).\left(1-\frac{3}{10}\right).\left(1-\frac{3}{13}\right)...\left(1-\frac{3}{97}\right).\left(1-\frac{3}{100}\right)\)
\(=\frac{1}{4}.\frac{4}{7}.\frac{7}{10}.\frac{10}{13}...\frac{94}{97}.\frac{97}{100}\)
\(=\frac{1.4.7.10...94.97}{4.7.10.13...97.100}=\frac{1}{100}.\)
\(A=\left(1+\frac{1}{2}\right)x\left(1+\frac{1}{3}\right)x\left(1+\frac{1}{4}\right)x...x\left(1+\frac{1}{100}\right)\)
\(A=\frac{3}{2}x\frac{4}{3}x\frac{5}{4}x...x\frac{101}{100}\)
\(A=\frac{101}{2}\)
A = \(\frac{3}{2}.\frac{4}{3}.\frac{5}{4}.....\frac{101}{100}\)
A = \(\frac{101}{2}\)
\(\Rightarrow Xx100+\left(1+2+3+...+100\right)=7400\)
\(\Rightarrow Xx100+\left[\left(100+1\right)x\left(100:2\right)\right]=7400\)
\(\Rightarrow Xx100+5050=7400\)
\(\Rightarrow Xx100=7400-5050\)
\(\Rightarrow Xx100=2350\)
\(\Rightarrow X=23,5\)
Vậy x=23,5
iem ko chắc đâu nhá
( 100 : 100 ) x 50000 : 10000 + 500
= 1 x 50000 : 10000 + 500
= 50000 : 10000 + 500
= 5 + 500
= 505
HT
@LeBaoPhuong
= 1 x 50000 : 10000 + 500
= 5 + 500
= 505