(205,189 x 97 + 205,189 x 3) x ( 89 – 8,9 : 0,1)
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0,1 : x + 1,2 : x + 2,3 : x + ...+ 8,9 : x = 13,5
\(\frac{1}{x}\times\left(0,1+1,2+2,3+...+8,9\right)=13,5.\)
\(\frac{1}{x}\times40,5=13,5\)
1/x = 1/3
=> x = 3
8,9 x 0,001 = 0,0089 0,09 x 0,1 = 0,009
3,14 x 0,01 = 0,0314 7,66 x 0,01 = 0,0766
500 x 0,001 = 0,5 0,07 x 0,001 = 0,00007
(8,9 x 14,7 + 2,5 x 14,7) x ( 34 x 11 - 3400 x 0,1 - 34)
= [14,7 x ( 8,9 + 2,5 )] x ( 374 - 340 - 34 )
= [ 14,7 x 11,4 ] x ( 34 - 34 )
= 167,58 x 0
= 0
(8,9×14,7+2,5×14,7)×(34×11−3400×0,1−34)
(8,9×14,7+2,5×14,7)×(34×11-3400×0,1-34)
=(8,9×14,7+2,5×14,7)×(34×11−34×10−34×1)=(8,9×14,7+2,5×14,7)×(34×11-34×10-34×1)
=(8,9×14,7+2,5×14,7)× (34×(11−10−1)=(8,9×14,7+2,5×14,7)× (34×(11-10-1)
=(8,9×14,7+2,5×14,7)×(34×0)=(8,9×14,7+2,5×14,7)×(34×0)
=(8,9×14,7+2,5×14,7)×0=(8,9×14,7+2,5×14,7)×0
=0
\(\frac{x+1}{99}+\frac{x+3}{97}+\frac{x+5}{95}=\frac{x+7}{93}+\frac{x+9}{91}+\frac{x+11}{89}\)
\(\Rightarrow\frac{x+1}{99}+1+\frac{x+3}{97}+1+\frac{x+5}{95}+1\)\(=\frac{x+7}{93}+1+\frac{x+9}{91}+1+\frac{x+11}{89}+1\)
\(\Rightarrow\frac{x+100}{99}+\frac{x+100}{97}+\frac{x+100}{95}\)\(=\frac{x+100}{93}+\frac{x+100}{91}+\frac{x+100}{89}\)
\(\Rightarrow\frac{x+100}{99}+\frac{x+100}{97}+\frac{x+100}{95}\)\(-\frac{x+100}{93}-\frac{x+100}{91}-\frac{x+100}{89}=0\)
\(\Rightarrow\left(x+100\right)\left(\frac{1}{99}+\frac{1}{97}+\frac{1}{95}-\frac{1}{93}-\frac{1}{91}-\frac{1}{89}\right)=0\)
Mà \(\left(\frac{1}{99}< \frac{1}{97}< \frac{1}{95}< \frac{1}{93}< \frac{1}{91}< \frac{1}{89}\right)\)nên \(\left(\frac{1}{99}+\frac{1}{97}+\frac{1}{95}-\frac{1}{93}-\frac{1}{91}-\frac{1}{89}\right)< 0\)
\(\Rightarrow x+100=0\Leftrightarrow x=-100\)
Vậy x = -100
\(\Leftrightarrow\dfrac{x+2+98}{98}+\dfrac{x+3+97}{97}=\dfrac{x+4+96}{96}+\dfrac{x+5+95}{95}\)
\(\Leftrightarrow\left(x+100\right)\left(\dfrac{1}{98}+\dfrac{1}{97}-\dfrac{1}{96}-\dfrac{1}{95}\right)=0\)
=>x+100=0
hay x=-100
(8,9 x 14,7 + 2,5 x 14,7) x (34 x 11 - 3400 x 0,1 - 34)
= (8,9 x 14,7 + 2,5 x 14,7) x (34 x 11 - 3400 : 10 - 34)
= [14,7 x (8,9 + 2,5)] x (34 x 11 - 34 x 10 - 34 x 1)
= (14,7 x 11,4) x [34 x (11 - 10 - 1)]
= (14,7 x 11,4) x (34 x 0)
= 0
( 14,7 x(8,9 + 2,5) ) x (34 x (11-100x0,1-1 )
=(14,7x11,4)x(34.(11-10-1))
=(14,7x11,4)x(34.0)
=(14,7x11,4)x0
=0
C1 :\(0,9\times95+1,8\times2+0,9\)
\(=0,9\times95+0,9\times2\times2+0,9\)
\(=0,9\times95+0,9\times4+0,9\)
\(=0,9\times\left(95+4+1\right)\)
\(=0,9\times100\)
\(=90\)
Cách 2 : \(0,9\times95+1,8\times2+0,9\)
\(=85,5+3,6+0,9\)
\(=90\)
câu thứ hai bn tự làm nha
Ta có: \(\left(\dfrac{1}{1\cdot2}+\dfrac{1}{2\cdot3}+\dfrac{1}{3\cdot4}+...+\dfrac{1}{8\cdot9}+\dfrac{1}{9\cdot10}\right)\cdot100-\left[\dfrac{5}{2}:\left(x+\dfrac{206}{100}\right)\right]:\dfrac{1}{2}=89\)
\(\Leftrightarrow100\cdot\dfrac{9}{10}-\left[\dfrac{5}{2}:\left(x+\dfrac{206}{100}\right)\right]:\dfrac{1}{2}=89\)
\(\Leftrightarrow\left[\dfrac{5}{2}:\left(x+\dfrac{103}{50}\right)\right]:\dfrac{1}{2}=1\)
\(\Leftrightarrow\dfrac{5}{2}:\left(x+\dfrac{103}{50}\right)=2\)
\(\Leftrightarrow x=-\dfrac{81}{100}\)
(205,189 x 97 + 205,189 x 3) x ( 89 – 8,9 : 0,1)
= [205,189 x (97 + 3)] x (89 - 89)
= (205,189 x 10) x 0
= 2051,89 x 0
= 0
chúc bn học tốt (rảnh thỳ k cho mk nha)
= (205,189 x (97 + 3)) x (89 - 89)
= (205,189 x 100) x 0
= 20518,9 x 0
= 0