=>x/27=1/9+3/27=1/9+1/9=2/9
=>x=6
`x/27+(-3/27)=1/9`
`=>x/27+(-1/9)=1/9`
`=>x/27=1/9-(-1/9)`
`=>x/27=1/9+1/9`
`=>x/27=2/9`
`=>x/27=6/27`
`=>x=6`
Vậy `x=6`
Bài 15:
a)\(\dfrac{-2}{5}\)+\(\dfrac{4}{5}\) . x =\(\dfrac{3}{5}\)
b)\(\dfrac{-3}{7}\) - \(\dfrac{4}{7}\):x = -2
Bài 16
a) x - \(\dfrac{10}{3}\) = \(\dfrac{7}{15}\) . \(\dfrac{3}{5}\)
b) x + \(\dfrac{3}{22}\)= \(\dfrac{27}{121}\) . \(\dfrac{11}{9}\)
c) \(\dfrac{8}{23}\) . \(\dfrac{48}{24}\) - x = \(\dfrac{1}{3}\)
d) 1 - x = \(\dfrac{49}{65}\).\(\dfrac{5}{7}\)
Bài 17: tìm x
a) \(\dfrac{62}{7}\) . x = \(\dfrac{29}{9}\): \(\dfrac{3}{56}\)
b) \(\dfrac{1}{5}\) : x=\(\dfrac{1}{5}\)+\(\dfrac{1}{7}\)
bài 18:
a)\(\dfrac{2}{5}\)+\(\dfrac{3}{4}\): x =\(\dfrac{-1}{2}\)
b)\(\dfrac{5}{7}\) - \(\dfrac{2}{3}\) . x = \(\dfrac{4}{5}\)
c) \(\dfrac{1}{2}\)x + \(\dfrac{3}{5}\)x = \(\dfrac{-2}{3}\)
d) \(\dfrac{4}{7}\).x-x = \(\dfrac{-9}{14}\)
bài 19: tính
\(\dfrac{1}{1.2}\)+\(\dfrac{1}{2.3}\)+\(\dfrac{1}{3.4}\)+...+ \(\dfrac{1}{2018.2019}\)
bài 20:tìm x
\(\dfrac{1}{1.2}\)+\(\dfrac{1}{2.3}\)+...+\(\dfrac{1}{x.\left(x+1\right)}\)=\(\dfrac{2008}{2009}\)
bài 21: tìm x
\(\dfrac{x+1}{99}\)+\(\dfrac{x+2}{98}\)\(\dfrac{x+3}{97}\)\(\dfrac{x+4}{96}\)=-4
bài 22 : so sánh các phân số sau:
a) \(\dfrac{-1}{5}\)+\(\dfrac{4}{-5}\)và 1
b) \(\dfrac{3}{5}\) và \(\dfrac{2}{3}\)+\(\dfrac{-1}{5}\)
c)\(\dfrac{3}{2}\)+\(\dfrac{-4}{3}\) và \(\dfrac{1}{10}\)+\(\dfrac{-4}{5}\)
d) \(\dfrac{1}{2}\)+\(\dfrac{1}{3}\)+\(\dfrac{1}{4}\)+\(\dfrac{1}{5}\)+\(\dfrac{1}{6}\) và 2
Cho 3 số nguyên dương a , b , c sao cho mỗi số nhỏ hơn tổng hai số kia . Chứng minh rằng :
\(\dfrac{a}{b+c}+\dfrac{b}{c+a}+\dfrac{c}{a+b}< 2\)
mấy bn giúp mik vs, mik đang cần gấp
Tìm x:
\(6\dfrac{2}{9}.x+3\dfrac{10}{27}=22\dfrac{1}{7}\)
giải giúp mình chi tiết nhé!!!
Chứng minh rằng : \(\dfrac{1}{26}+\dfrac{1}{27}+\dfrac{1}{28}+...+\dfrac{1}{50}=1-\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}+...+\dfrac{1}{49}+\dfrac{1}{50}\)
Bài 1: Tìm số nguyên x, biết:
a)\(\dfrac{6}{x-3}\) = \(\dfrac{2}{3}\)
b) \(\dfrac{14}{13}\) = \(\dfrac{-28}{10-x}\)
c) \(\dfrac{1}{5}\) = \(\dfrac{x:4-1}{10}\)
d) \(\dfrac{x}{4}\)= \(\dfrac{1}{x}\)
e) \(\dfrac{x-2}{50}\) = \(\dfrac{2}{x-2}\)
giúp ưm
1, Tìm x,y∈ Z, biết:
a) \(\dfrac{-x}{4}\)=\(\dfrac{-9}{x}\)
b) \(\dfrac{x}{7}\)=\(\dfrac{9}{y}\)(x>y)
c) \(\dfrac{x}{4}\)=\(\dfrac{18}{x+1}\)
d) \(\dfrac{-2}{x}\)=\(\dfrac{y}{5}\)(x<0<y)
e) \(\dfrac{x-4}{y-3}\)=\(\dfrac{4}{3}\)(x-y=5)
Giải giúp mik nhé
Ai nhanh mik tick cho
Hạn hôm nay đến ngày mai ạ, các bạn nhanh nhá
Thanks you very much!!!
\(\dfrac{x}{6}\)= \(\dfrac{3}{5}\)+ \(\dfrac{\left(-17\right)}{30}\)
giúp mik vs nha!
mik xin cám ơn!
Tìm x,y biết
a) \(\dfrac{-5}{6}.\dfrac{120}{25}< x< \dfrac{-7}{15}.\dfrac{9}{14}\)
b) \(\left(\dfrac{-5}{3}\right)^2< x< \dfrac{-24}{35}.\dfrac{-5}{6}\)
c) \(\dfrac{1}{18}< \dfrac{x}{12}< \dfrac{y}{9}< \dfrac{1}{4}\)
d) \(\dfrac{x-4}{y-3}=\dfrac{4}{3}\) và x-y = 5
Nhanh nha đến ngày 20/7
\(-31\dfrac{4}{9} - 5 . ( \dfrac{2}{3} . x + 1\dfrac{1}{2})=-21\dfrac{4}{9}\)
