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a, \(A=\frac{10^8+2}{10^8-1}=\frac{10^8-1+3}{10^8-1}=1+\frac{3}{10^8-1}\)
\(B=\frac{10^8}{10^8-3}=\frac{10^8-3+3}{10^8-3}=1+\frac{3}{10^8-3}\)
Vì \(\frac{3}{10^8-1}< \frac{3}{10^8-3}\Rightarrow1+\frac{3}{10^8-1}< 1+\frac{3}{10^8-3}\Rightarrow A< B\)
b, \(A=\frac{10^{15}+1}{10^{16}+1}\Rightarrow10A=\frac{10\left(10^{15}+1\right)}{10^{16}+1}=\frac{10^{16}+10}{10^{16}+1}=\frac{10^{16}+1+9}{10^{16}+1}=1+\frac{9}{10^{16}+1}\)
\(B=\frac{10^{16}+1}{10^{17}+1}\Rightarrow10B=\frac{10\left(10^{16}+1\right)}{10^{17}+1}=\frac{10^{17}+10}{10^{17}+1}=\frac{10^{17}+1+9}{10^{17}+1}=1+\frac{9}{10^{17}+1}\)
Vì \(\frac{9}{10^{16}+1}>\frac{9}{10^{17}+1}\Rightarrow1+\frac{9}{10^{16}+1}>1+\frac{9}{10^{17}+1}\Rightarrow10A>10B0\Rightarrow A>B\)
c, giống câu b
d, giống câu b
e, \(A=\frac{10^{15}+5}{10^{15}-7}=\frac{10^{15}-7+12}{10^{15}-7}=1+\frac{12}{10^{15}-7}\)
\(B=\frac{10^{16}+7}{10^{16}-5}=\frac{10^{16}-5+12}{10^6-5}=1+\frac{12}{10^6-5}\)
Vì \(\frac{12}{10^{15}-7}>\frac{12}{10^{16}-5}\Rightarrow1+\frac{12}{10^{15}-7}>1+\frac{12}{10^{16}-7}\Rightarrow A>B\)
f, \(A=\frac{20^{10}+1}{20^{10}-1}=\frac{20^{10}-1+2}{20^{10}-1}=1+\frac{2}{20^{10}-1}\)
\(B=\frac{20^{10}-1}{20^{10}-3}=\frac{20^{10}-3+2}{20^{10}-3}=1+\frac{2}{20^{10}-3}\)
Vì \(\frac{2}{20^{10}-1}< \frac{2}{20^{10}-3}\Rightarrow1+\frac{2}{20^{10}-1}< 1+\frac{2}{20^{10}-3}\Rightarrow A< B\)
e, Ta có:
\(A-B=\left(\frac{-7}{10^{2013}}+\frac{-15}{10^{2014}}\right)-\left(\frac{-15}{10^{2013}}+\frac{-7}{10^{2014}}\right)\)
\(=\frac{-7}{10^{2013}}+\frac{-15}{10^{2014}}-\frac{-15}{10^{2013}}-\frac{-7}{10^{2014}}\)
\(=\frac{8}{10^{2013}}-\frac{8}{10^{2014}}>0\)
Vậy A > B
Phần a;b;c;d;e;f liên quan tới
\(\frac{a}{b}< \frac{a+c}{b+c}\forall a< b\) \(\frac{a}{b}>\frac{a+c}{b+c}\forall a>b\) phép trừ thì ngược lại
Giải phần g
\(A=\frac{-7}{10^{2013}}+\frac{-7}{10^{2014}}+\frac{-8}{10^{2014}}\)
\(B=\frac{-7}{10^{2013}}+\frac{-8}{10^{2013}}+\frac{-7}{10^{2014}}\)
có đcB>A
k minh nha
Minh chi biet lam cau b thoi ak
b) Giai:
B=10^16+1 tren 10^17 +1 <10^16+1+9 tren 10^17+1+9
ma 10^16+1+9 tren 10^17+1+9 = 10^16+10 tren 10^17+10
=10(10^15+1) tren 10(10^16+1)
=10^15+1 tren 10^16+1 =A
=>A>B
Cho y kien voi!
ta có;
b=8/3.2/5.3/8.10.19/92
b=16/15.3/8.10.19/92
b=2/5.10.19/92
b=4.19/92
b=19/23
c=-5/7.2/7+-5/7 . 9/14+1/5/7
c=-10/49+(-45)/98+1/5/5
c=131/98
a)\(\frac{-5}{13}+\left(\frac{3}{5}+\frac{3}{13}-\frac{4}{10}\right)=\frac{-5}{13}-\frac{3}{5}-\frac{3}{13}+\frac{4}{10}=\left(\frac{-5}{13}-\frac{3}{13}\right)+\frac{4}{10}-\frac{3}{5}=\frac{-5-3}{13}+\left(\frac{4}{10}-\frac{6}{10}\right)=\frac{-8}{13}+\frac{-2}{10}=\frac{-80}{130}+\frac{-26}{130}=\frac{-106}{130}=\frac{-53}{65}\)
nói chuyện với mk đi
nói làm j