Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
trả lời
tui trả lời rui mà
chúc bà học tốt
nhớ k tui nha
cám ơn các bn
a)
\(\frac{2}{3}\div x-\frac{1}{2}=\frac{1}{3}\)
\(\Rightarrow\frac{2}{3}\div x=\frac{1}{3}+\frac{1}{2}\)
\(\Rightarrow\frac{2}{3}\div x=\frac{5}{6}\)
\(\Rightarrow x=\frac{2}{3}\div\frac{5}{6}\)
\(\Rightarrow x=\frac{4}{5}\)
Vậy \(x=\frac{4}{5}\)
b)
\(\frac{3}{4}.x+\frac{2}{5}=\frac{5}{2}\)
\(\Rightarrow\frac{3}{4}.x=\frac{5}{2}-\frac{2}{5}\)
\(\Rightarrow\frac{3}{4}.x=\frac{21}{10}\)
\(\Rightarrow x=\frac{21}{10}\div\frac{3}{4}\)
\(\Rightarrow x=\frac{14}{5}\)
Vậy \(x=\frac{14}{5}\)
Các bước chi tiết mình không trình bày ra nha.
a) 2/3:x-1/2=1/3
2/3:x=1/3+1/2
2/3:x=5/6
x=2/3:5/6
x=4/5
b) 3/4.x+2/5=5/2
3/4.x=5/2-2/5
3/4.x=21/10
x=21/10:3/4
x=14/5
1.\(\frac{4}{3.7}+\frac{4}{7.11}+\frac{4}{11.15}+\frac{4}{15.19}+\frac{4}{19.23}+\frac{4}{23.27}\)
\(=\frac{1}{3}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+...+\frac{4}{23}-\frac{4}{27}\)
\(=\frac{1}{3}-\frac{1}{27}=\frac{9}{27}-\frac{1}{27}=\frac{8}{27}\)
2. Đặt \(A=\frac{3}{14}+\frac{3}{84}+\frac{3}{204}+\frac{3}{374}+\frac{3}{594}+\frac{3}{864}\)
\(\Rightarrow A=\frac{3}{2.7}+\frac{3}{7.12}+...+\frac{3}{27.32}\)
\(\Rightarrow5A=3.\left(\frac{5}{2.7}+\frac{5}{7.12}+...+\frac{5}{27.32}\right)\)
\(\Rightarrow5A=3.\left(\frac{1}{2}-\frac{1}{7}+\frac{1}{7}-\frac{1}{12}+...+\frac{1}{27}-\frac{1}{32}\right)\)
\(\Rightarrow5A=3.\left(\frac{1}{2}-\frac{1}{32}\right)\)
\(\Rightarrow5A=3.\frac{15}{32}=\frac{45}{32}\Rightarrow A=\frac{45}{32}:5=\frac{9}{32}\)
3. Đặt \(S=\frac{1}{10}+\frac{1}{40}+\frac{1}{88}+...+\frac{1}{340}\)
\(\Rightarrow3S=\frac{3}{10}+\frac{3}{40}+...+\frac{3}{340}\)
\(\Rightarrow3S=\frac{3}{2.5}+\frac{3}{5.8}+...+\frac{3}{17.20}\)
\(\Rightarrow3S=\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...+\frac{1}{17}-\frac{1}{20}\)
\(\Rightarrow3S=\frac{1}{2}-\frac{1}{20}=\frac{9}{20}\Rightarrow S=\frac{9}{20}:3=\frac{3}{20}\)
Câu 1:
\(\frac{4}{3.7}+\frac{4}{7.11}+\frac{4}{11.15}+\frac{4}{15.19}+\frac{4}{19.23}+\frac{4}{23.27}\)
\(\Rightarrow\frac{1}{3}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+\frac{1}{11}-\frac{1}{15}+\frac{1}{15}-\frac{1}{19}+\frac{1}{19}-\frac{1}{23}+\frac{1}{23}-\frac{1}{27}\)
\(\Rightarrow\frac{1}{3}-\frac{1}{27}\)
\(=\frac{8}{27}\)
b,(6,27+158,61-27)x(4,5x2-90:10)
=(6,27+158,61-27)x(9-9)
=(6,27+158,61-27)x0
=0
theo mk là
A thì = tất cả các phân số có tử bé hơn mẫu lên cho là bé hơn 1
B = 3
vậy B > A
Tính làm sao cũng được
tùy theo cách tính ( tự tìm A)
theo tui tính
A=3
B=3
=> A=B
1/1 x 2 + 1/2 x 3 + 1/3 x 4 + ... + 1/999 x 1000 + 1
= 1/1 - 1/1000 + 1
= 999/1000 + 1
= 1999/1000
Chuc ban may man
\(5\frac{9}{10}:\frac{3}{2}-\left(2\frac{1}{3}x4\frac{1}{2}-2\frac{1}{2}\right):\frac{7}{4}\)
=\(\frac{59}{10}:\frac{3}{2}-\left(\frac{7}{3}x\frac{9}{2}-\frac{5}{2}\right):\frac{7}{4}\)
=\(\frac{118}{30}-\left(\frac{63}{6}-\frac{5}{2}\right)x\frac{4}{7}\)
=\(\frac{118}{30}-\left(\frac{63}{6}-\frac{15}{6}\right)x\frac{4}{7}\)
=\(\frac{118}{30}-8x\frac{4}{7}\)
=\(\frac{118}{30}-\frac{32}{7}\)
sau bn tự tính nha
1) \(1+\frac{1}{3}+1\frac{91}{27}+\frac{1}{81}\)
\(=1+\frac{1}{3}+4+\frac{10}{27}+\frac{1}{81}\)
\(=\left(1+4\right)+\left(\frac{1}{3}+\frac{10}{27}+\frac{1}{81}\right)\)
\(=5+\frac{58}{81}=5\frac{58}{81}\)
2) \(\frac{1}{78}+\frac{1}{91}+\frac{1}{105}+\frac{1}{120}+\frac{1}{136}\)
\(=\frac{1}{6\times13}+\frac{1}{13\times7}+\frac{1}{7\times15}+\frac{1}{15\times8}+\frac{1}{8\times17}\)
\(=\frac{1}{6}-\frac{1}{13}+\frac{1}{13}-\frac{1}{7}+\frac{1}{7}-\frac{1}{15}+\frac{1}{15}-\frac{1}{8}+\frac{1}{8}-\frac{1}{17}\)
(gạch bỏ các số giống nhau)
\(=\frac{1}{6}-\frac{1}{17}=\frac{11}{102}\)
3) \(\frac{1}{6}+\frac{1}{30}+\frac{1}{70}+\frac{1}{126}\)
\(=\frac{1}{2\times3}+\frac{1}{3\times10}+\frac{1}{10\times7}+\frac{1}{7\times18}\)
\(=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{10}+\frac{1}{10}-\frac{1}{7}+\frac{1}{7}-\frac{1}{18}\)
\(=\frac{1}{2}-\frac{1}{18}=\frac{4}{9}\)
chúc bn học tốt!!
công chúa ôri ơi mk viết nhầm đề bài 1
đề bài là 1+1/3+1/9+1/27+1/81
bạn trả lời giúp mk với mk cần gấp lắm
cảm ơn
