328-327-326=327.(328-27-1)-326=327.(3-1)-326=327.2-326
328-327-326=327.(328-27-1)-326=327.(3-1)-326=327.2-326=3.2.326-326=6.326-326=326.(6-1)=326.5
\(3^{28}-3^{27}-3^{26}=3^{26}\left(3^2-3-1\right)=3^{26}\cdot5\)
328-327-326=327.(328-27-1)-326=327.(3-1)-326=327.2-326
328-327-326=327.(328-27-1)-326=327.(3-1)-326=327.2-326=3.2.326-326=6.326-326=326.(6-1)=326.5
\(3^{28}-3^{27}-3^{26}=3^{26}\left(3^2-3-1\right)=3^{26}\cdot5\)
Chứng minh rằng:
\(\frac{1}{1.2}+\frac{1}{3.4}+\frac{1}{5.6}+....+\frac{1}{49.50}=\frac{1}{26}+\frac{1}{27}+\frac{1}{28}+...+\frac{1}{50}\)
Chứng minh rằng:
\(\frac{1}{1.2}+\frac{1}{3.4}+\frac{1}{5.6}+...+\frac{1}{49.50}=\frac{1}{26}+\frac{1}{27}+\frac{1}{28}+...+\frac{1}{50}\)
hép mi
\(\dfrac{x+4}{2000}+\dfrac{x+3}{2001}=\dfrac{x+2}{2002}+\dfrac{x+1}{2003}\)
1/* Chứng minh rằng:
\(\dfrac{1}{1\times2}+\dfrac{1}{3\times4}+\dfrac{1}{5\times6}+...\dfrac{1}{49\times50}=\dfrac{1}{26}+\dfrac{1}{27}+\dfrac{1}{28}+..+\dfrac{1}{50}\)
2/* Cho:
A=\(\dfrac{1}{1\times2}+\dfrac{1}{3\times4}+\dfrac{1}{5\times6}+.....+\dfrac{1}{99\times100}\). Chứng minh rằng:\(\dfrac{7}{12}< A>\dfrac{5}{6}\)
Các bn giúp mk những bài này nha!
Trong các số sau ,số nào biểu diễn số hữu tỉ \(\dfrac{3}{-4}\)?
\(\dfrac{-12}{15};\dfrac{-15}{20};\dfrac{24}{-32};\dfrac{-20}{28};\dfrac{-27}{36}\)
26 1/5×3/4-3/4×44 1/5
\((\dfrac{1}{3})^x+(\dfrac{1}{3})^{x+3}=\dfrac{28}{243}\)
\((\dfrac{1}{3})^x+(\dfrac{1}{3})^{x+3}=\dfrac{28}{243}\)
4/15-23/28-(-23/28+ -11/5-29/27)-2/27
CỨU TOII VỚI
( x - 1/3 ) mũ 3 = -8/27