Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
A=\(\dfrac{-2}{9}\)+\(\dfrac{-3}{4}\)+\(\dfrac{3}{5}\)+\(\dfrac{1}{15}\)+\(\dfrac{1}{57}\)+\(\dfrac{1}{3}\)+\(\dfrac{-1}{36}\)
A=(\(\dfrac{-2}{9}\)+\(\dfrac{-3}{4}\)+\(\dfrac{-1}{36}\))+(\(\dfrac{3}{5}\)+\(\dfrac{1}{15}\)+\(\dfrac{1}{3}\))
A=-1+1=0 B=\(\dfrac{1}{2}\)+\(\dfrac{-1}{5}\)+\(\dfrac{-5}{7}\)+\(\dfrac{1}{6}\)+\(\dfrac{-3}{35}\)+\(\dfrac{1}{3}\)+\(\dfrac{1}{41}\) B=(\(\dfrac{-1}{5}\)+\(\dfrac{-5}{7}\)+\(\dfrac{-3}{35}\))+(\(\dfrac{1}{2}\)+\(\dfrac{1}{6}\)+\(\dfrac{1}{3}\))+\(\dfrac{1}{41}\) B=-1+1+\(\dfrac{1}{41}\)=\(\dfrac{1}{41}\)
câu 1 : A=-2/9+-3/4+3/5+1/15+1/57+1/3+-1/36
=(-2/9+-3/4+-1/36)+(3/5+1/15+1/3)
Vậy p/s 1/57 đâu bạn ?
a) \(\frac{-1}{2}+\frac{-1}{9}-\frac{-3}{5}+\frac{1}{2006}-\frac{-2}{7}-\frac{7}{18}+\frac{4}{35}\)
\(=\left(\frac{-1}{2}-\frac{1}{9}-\frac{7}{18}\right)+\left(\frac{3}{5}+\frac{4}{35}\right)+\frac{1}{2006}\)
\(=\left(\frac{-9}{18}-\frac{2}{18}-\frac{7}{18}\right)+\left(\frac{21}{35}+\frac{4}{35}\right)+\frac{1}{2006}\)
\(=\left(\frac{-9-2-7}{18}\right)+\left(\frac{21+4}{35}\right)+\frac{1}{2006}\)
\(=\left(\frac{-18}{18}\right)+\left(\frac{25}{35}\right)+\frac{1}{2006}\)
\(=\left(-1\right)+\frac{5}{7}+\frac{1}{2006}\)\(=\frac{-4005}{14042}\)
b) \(\frac{1}{3}-\frac{3}{4}+\frac{3}{5}+\frac{1}{2007}-\frac{1}{36}+\frac{1}{15}-\frac{2}{9}\)
\(=\left(\frac{1}{3}+\frac{1}{2007}-\frac{2}{9}\right)-\left(\frac{3}{4}+\frac{1}{36}\right)+\left(\frac{3}{5}+\frac{1}{15}\right)\)
\(=\left(\frac{669}{2007}+\frac{1}{2007}-\frac{446}{2007}\right)-\left(\frac{27}{36}+\frac{1}{36}\right)+\left(\frac{9}{15}+\frac{1}{15}\right)\)
\(=\frac{224}{2007}-\frac{28}{36}+\frac{10}{15}\)
\(=\frac{224}{2007}-\frac{1561}{2007}+\frac{1338}{2007}\)\(=\frac{1}{2007}\)
1) (1-3/4 + 2/7) - ( 1/4 - 2/5 - 1)
= 1 - 3/4 + 2/7 - 1/4 + 2/5 + 1
= (1 - 3/4 - 1/4) + (2/7 + 2/5 +1)
= 0 + 59/35
= 59/35
2) -3/5 * 7/8 + (-3)/8 * 13/5
= -3*7/5*8 + -3*13/8*5
= -3/8 * 7/5 + -3/8 * 13/5
= -3/8 * (7/5 + 13/5)
= -3/8 * 4
= -3/2
3) -3/4 * 3/7 - 12/7 * 1/4 + 3/4 * (-9)/7
= 3/4 * -3/7 - 3*4/7 * 1/4 + 3/4 * (-9)/7
= 3/4 * -3/7 - 3/4 * 4/7 + 3/4 * -9/7
= 3/4 * (-3/7 - 4/7 - 9/7)
= 3/4 * -16/7
= -12/7
5) 1/3 - 3/4 + 3/5+ 1/57 -1/36 + 1/15 - 2/9
= (1/3 - 3/4 - 1/36 - 2/9) + (3/5 + 1/15) + 1/57
= (12/36 - 27/36 - 1/36 - 8/36) + (9/15 + 1/15) + 1/57
= -2/3 + 2/3 + 1/57
= 0 + 1/57
= 1/57
6) 0,5 + 1/3 - 0,4 - 5/7 + 1/6 + 4/35 + 1/41
= 1/2 + 1/3 - 2/5 - 5/7 + 1/6 + 4/35 + 1/41
= (1/2 + 1/3 + 1/6) + (4/35 - 2/5 - 5/7) + 1/41
= (3/6 + 2/6 + 1/6) + (4/35 - 14/35 - 25/35) + 1/41
= 1 + (-1) + 1/41
= 0 + 1/41
=1/41
Chúc bạn học tốt!
\(\dfrac{1}{2}-\dfrac{1}{5}+\dfrac{-5}{7}+\dfrac{1}{6}-\dfrac{3}{35}+\dfrac{1}{3}-\dfrac{-1}{41}\)
\(=\left(\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{6}\right)+\left(-\dfrac{1}{5}-\dfrac{5}{7}-\dfrac{3}{35}\right)+\dfrac{1}{41}\)
\(=\dfrac{3+2+1}{6}+\dfrac{-7-25-3}{35}+\dfrac{1}{41}\)
\(=\dfrac{6}{6}+\dfrac{-35}{35}+\dfrac{1}{41}=\dfrac{1}{41}\)
