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0,25 X x = 0,75+0,25
0,25 X x = 1
x = 1:0,25
x = 4
x : 1.25 =1/4 - 0,25
x : 1,25 = 0,75
x = 0,75 x 1,25
x = 0,9375
0,25 X x = 0,75+0,25
0,25 X x = 1
x = 1:0,25
x = 4
0,25 x x = 0,75+0,25
0,25x x = 1
x = 1 : 0,25
x = 4
x : 1,25 =\(\frac{1}{4}\) - 0,25
x : 1,25 = \(\frac{1}{4}-\frac{25}{100}\)
x : 1,25 = \(\frac{1}{4}-\frac{1}{4}\)
x : 1,25 = 0
x = 0 x 1,25
x = 0
0,25 x x = 0,75+0,25
0,25x x = 1
x = 1 : 0,25
x = 4
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\(=\left(\frac{75}{100}+\frac{65}{100}+\frac{1}{4}+\frac{35}{100}\right)\left(\frac{1}{4}.2+\frac{25}{100}.3+\frac{25}{100}.5\right)\)
\(=\left(\frac{3}{4}+\frac{13}{20}+\frac{1}{4}+\frac{7}{20}\right)\left(\frac{2}{4}+\frac{3}{4}+\frac{5}{4}\right)\)
\(=\left(1+1\right).\frac{10}{4}\)
\(=2.\frac{5}{2}\)
\(=5\)
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1) 9 x 10 + 10 x 11 + 11 x 12 + ....+ 2015 x 2016
=9x10x11-8x9x10+10x11x12-9x10x11+...+2015x2016x2017-2014x2015x2013
=2015x2016x2017-8x9x10
=8193537360
1/2 *x+3/4*x+ 1/4*x-1/2*x=2015
(1/2+3/4+1/4-1/2)*x=2015
1*x=2015
x=2015:1
=>x=2015
mk ko biết