143÷3=?
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
c)(145x99+145)-(143x102-143)
= 145x(99+1)-143x(101-1)
= 145x100-143x100
= (145-143)x100
= 2x100
= 200
\(\frac{-3}{15}+\frac{-3}{35}+\frac{-3}{63}+\frac{-3}{99}+\frac{-3}{143}+\frac{-3}{195}\)
\(=\frac{-3}{3.5}+\frac{-3}{5.7}+\frac{-3}{7.9}+\frac{-3}{9.11}+\frac{-3}{11.13}+\frac{-3}{13.15}\)
\(=\frac{-3}{2}\left(\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}+\frac{2}{9.11}+\frac{2}{11.13}+\frac{2}{13.25}\right)\)
\(=\frac{-3}{2}\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}+\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}\right)\)
\(=\frac{-3}{2}.\left(\frac{1}{3}-\frac{1}{15}\right)=\frac{-3}{2}.\frac{4}{15}=\frac{-2}{5}\)
- (-15) – (-3 +15 – 8)
= 15 + 3 - 15 + 8
= 11
b) + ( - 143 + 17 – 35) – ( -143 + 37 – 35)
= -143 + 17 - 35 + 143 - 37 + 35
= -20
c) 50 - ( 47 + 50 - 18 ) - ( 47 + 18 )
= 50 - 47 - 50 + 18 - 47 - 18
= -47 - 47
= -94
d) 16 - ( -15 ) + ( -20 ) - | -24 |
= 16 + 15 - 20 - 24
= -13
\(\frac{3}{3}+\frac{3}{15}+\frac{3}{35}+...+\frac{3}{143}\)
\(=\frac{3}{1.3}+\frac{3}{3.5}+\frac{3}{5.7}+...+\frac{3}{11.13}\)
\(=\frac{3}{2}.\left(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{11.13}\right)\)
\(=\frac{3}{2}.\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{11}-\frac{1}{13}\right)\)
\(=\frac{3}{2}.\left(1-\frac{1}{13}\right)\)
\(=\frac{3}{2}.\frac{12}{13}\)
\(=\frac{18}{13}\)
_Chúc bạn học tốt_
\(\frac{3}{3}+\frac{3}{15}+\frac{3}{35}+\frac{3}{63}+...+\frac{3}{143}\)
\(=\frac{3}{1.3}+\frac{3}{3.5}+\frac{3}{5.7}+\frac{3}{7.9}+...+\frac{3}{11.13}\)
\(=\frac{3}{2}\left(\frac{2}{1.3}+\frac{2}{3.5}+....+\frac{2}{11.13}\right)\)
\(=\frac{3}{2}\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+....+\frac{1}{11}-\frac{1}{13}\right)\)
\(=\frac{3}{2}\left(1-\frac{1}{13}\right)\)
\(=\frac{3}{2}.\frac{12}{13}=\frac{18}{13}\)
143:3=47(dư 2)
143:3=47 ( dư 5 )