So sánh hai phân số: A = 20\39 + 22\27 + 18\43 và B = 14\39 + 22\39 + 18\41.
Rút gọn phân số : 199 .......9 \ 999....... 9.
So sánh hai phân số: A = 20\39 + 22\27 + 18\43 và B = 14\39 + 22\39 + 18\41.
Rút gọn phân số : 199 .......9 \ 999....... 9.
Tìm x 1) : x-1\10 + x-1\11 = x-1\12 + x-1\13.
2): x-2000\10 + x-1999\9 = x-1998\8 + x-1997\7.
Bài 3:
\(a,\dfrac{x-1}{10}+\dfrac{x-1}{11}=\dfrac{x-1}{12}+\dfrac{x-1}{13}\)
\(\Rightarrow\dfrac{x-1}{10}+\dfrac{x-1}{11}-\dfrac{x-1}{12}-\dfrac{x-1}{13}=0\)
\(\Rightarrow\left(x-1\right)\left(\dfrac{1}{10}+\dfrac{1}{11}-\dfrac{1}{12}-\dfrac{1}{13}\right)=0\)
Mà \(\dfrac{1}{10}+\dfrac{1}{11}-\dfrac{1}{12}-\dfrac{1}{13}\ne0\)
\(\Rightarrow x-1=0\Rightarrow x=1\)
Vậy x = 1
b, \(\dfrac{x-2000}{10}+\dfrac{x-1999}{9}=\dfrac{x-1998}{8}+\dfrac{x-1997}{7}\)
\(\Rightarrow\dfrac{x-2000}{10}+1+\dfrac{x-1999}{9}+1=\dfrac{x-1998}{8}+\dfrac{x-1997}{7}+1\)
\(\Rightarrow\dfrac{x-1990}{10}+\dfrac{x-1990}{9}-\dfrac{x-1990}{8}-\dfrac{x-1990}{7}=0\)
\(\Rightarrow\left(x-1990\right)\left(\dfrac{1}{10}+\dfrac{1}{9}-\dfrac{1}{8}-\dfrac{1}{7}\right)=0\)
Mà \(\dfrac{1}{10}+\dfrac{1}{9}-\dfrac{1}{8}-\dfrac{1}{7}\ne0\)
\(\Rightarrow x-1990=0\Rightarrow x=1990\)
so sánh
a= 20/39 + 22/27 + 18/43
b= 14/39 +22/29 +18/41
Ta thấy :
\(\frac{20}{39}>\frac{14}{39}\)
\(\frac{22}{27}>\frac{22}{29}\)
\(\frac{18}{43}< \frac{18}{41}\)
\(\Rightarrow\frac{20}{39}+\frac{22}{27}+\frac{18}{43}>\frac{14}{39}+\frac{22}{29}+\frac{18}{41}\)
=> A > B
so sánh A và B :
A = \(\frac{20}{39}+\frac{22}{27}+\frac{18}{43}\), B = \(\frac{14}{39}+\frac{22}{29}+\frac{18}{41}\)
ta có 20/39 > 14/39
22/27 > 22/29
18/43 < 18/41
=> 20/39+22/27+18/43 > 14/39+22/29+18/41
ta có 20/39 > 14/39
22/27 > 22/29
18/43 < 18/41
=> 20/39+22/27+18/43 > 14/39+22/29+18/41
Bằng dấu lớn ( > ) bạn nhé!^-^
Chúc bạn học tốt nha!^-^
so sánh \(A=\frac{20}{39}+\frac{22}{27}+\frac{18}{43};B=\frac{14}{39}+\frac{22}{29}+\frac{18}{41}\)
So sánh A và B:
A=20/39+22/27+18/43 ; B=14/39+22/29+18/41
so sanh A=20/39+22/27+18/43 va B=14/39+22/29+18/41
giai mau giup minh voi
xét A và B,ta thấy:
20/39>14/39
22/27>22/29
18/43<18/41
Ta có: 20/39+22/27>14/39+22/29
2012^2013+2013^2013<2013^2013+2013^2014
xet A va B ta thay:
20/39>14/39
22/27>22/29
18/43<18/41
vay A>B
so sánh bằng cách nhanh nhất :
22/35 và 103/177
14/39 + 22/39+18/41 và 20/39 + 22/27 +18/43
CÁC BN TRẢ LỜI NHANH CHO MIK NHÉ MIK ĐÂNG RẤT VỘI !!!!!!!!!!!!!!!!
So sánh A và B :
a,A=20/39+22/27+18/43 B=14/39+22/29+18/41
3 like cho ai làm được
xét A và B, ta thấy:
20/39>14/39
22/27>22/29
18/43<18/41
Ta có: 20/39+22/27>14/39+22/29
2012^2013+2013^2013<2013^2013+2013^2014
So sanh AvaB
A=\(\dfrac{20}{39}+\dfrac{22}{27}+\dfrac{18}{43},B=\dfrac{14}{39}+\dfrac{22}{29}+\dfrac{18}{41}\)
Ta có: \(\dfrac{20}{39}>\dfrac{20}{41}>\dfrac{18}{41}\left(1\right)\)
\(\dfrac{22}{27}>\dfrac{22}{29}\left(2\right)\)
\(\dfrac{18}{43}=1-\dfrac{25}{43};\dfrac{14}{39}=1-\dfrac{25}{39}\)
Vì \(\dfrac{25}{43}< \dfrac{25}{39}\Rightarrow1-\dfrac{25}{43}>1-\dfrac{25}{39}\Rightarrow\dfrac{18}{43}>\dfrac{14}{39}\left(3\right)\)
Từ \(\left(1\right);\left(2\right);\left(3\right)\) ta suy ra : A>B