A=2/1x3+2/3x5+2/5x7+....+2/99x101
Tính bằng cách thuận tiện.
A=5/9+2/15-6/9
B=2/7-3/8+4/7+1/7-5/8+5/15
C=3/5+1/15+1/57+1/3-2/9-3/4-1/36
D=1/1x2+1/2x3+1/3x4+...+1/99x100
E=1-3/1x3-3/3x5-3/5x7-...-19
help plssssssss
1x3+3x5+5x7+...+19x21 tính tổng
Bn cho mk cách giải
1x3+3x5+5x7+...+99x101
Tính bằng cách thuận tiện nhất
a -(12/46 +15/21) +(3/7-7/23)
b(-21+-7/-9)-(6/34-25/9)
c (21/8--13/-26)+(34/16--12/52)
a=1/1x3=1/3x5+1/5x7+....+1/2019x2021+1/2021x2023
(1/3x5+1/5x7+1/7x9+.....+1/19x21)*x=9/7
1x3+3x5+5x7+...+97x99
1)\(\frac{4}{7}:\frac{-15}{28}x\left(-3\right)^2\) 2)\(\frac{15}{49}x1,4-\left(\frac{2}{3}+\frac{4}{5}\right);\frac{22}{10}\) 3)\(\frac{1}{4}-\frac{7}{4}:\left(-7\right)-3:\frac{3}{4}x\left(-2\right)^{^2}\)
4)\(\frac{5}{1x3}+\frac{5}{3x5}+\frac{5}{5x7}+....\frac{5}{197x199}\)