a)\(\dfrac{1}{x}+\dfrac{1}{y}\) =1
\(\Rightarrow\dfrac{y}{xy}+\dfrac{x}{xy}=\dfrac{xy}{xy}\)
\(\Rightarrow y+x=xy\)
\(\Rightarrow xy-x-y=0\)
đẻ thỏa mãn trường hớp trên suy ra cặp giá trị của( x ,y) sẻ là (1,1);(2,2)
Tìm x, y \(\in\) Z biết :
a) \(\dfrac{x}{y-1}=\dfrac{2}{-3}\)
b) \(\dfrac{1}{x}+\dfrac{1}{y}=\dfrac{1}{2}\)
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!!!
tính
\(\dfrac{1}{1+2}+\dfrac{1}{1+2+3}+\dfrac{1}{1+2+3+4}+...+\dfrac{1}{1+2+...+50}\)
giúp mk nha ai nhanh nhất mk tick cho*_*
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
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
bài 20 : tìm x
\(\dfrac{1}{1.2}\)+\(\dfrac{1}{2.3}\)+...+ \(\dfrac{1}{x.\left(x+1\right)}\)+\(\dfrac{1}{2018.2019}\)
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
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
a) (\(\dfrac{11}{12}+\dfrac{11}{12.23}+\dfrac{11}{23.34}+....+\dfrac{11}{89.100}\))+ x =\(\dfrac{5}{3}\)
b) (\(\dfrac{5}{11.16}+\dfrac{5}{16.21}+...+\dfrac{5}{19.24}\))- x + \(\dfrac{1}{3}=\dfrac{7}{3}\)
c) \(\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{10}+...+\dfrac{2}{x\left(x+1\right)}=\dfrac{1999}{2001}\)
Giúp mình nhé mấy bạn. Mai mình phải nộp rùi. Ai làm nhanh mình tick cho nha
Bài 4: Tìm các cặp x, y sao cho:
a) \(\dfrac{x}{3}\)-\(\dfrac{4}{y}\)=\(\dfrac{1}{5}\)
b) \(\dfrac{5}{x-1}\)-\(\dfrac{y-1}{3}\)=\(\dfrac{1}{6}\)
Tìm x , y biết :
a / \(\dfrac{-5}{x}\)= \(\dfrac{y}{16}\) = \(\dfrac{-18}{72}\)
b / \(\dfrac{1}{2}\) = \(\dfrac{x-1}{8}\) = \(\dfrac{10}{y-5}\)
