Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(\left(1-\frac{1}{6}\right)x\left(1-\frac{1}{7}\right)x\left(1-\frac{1}{8}\right)x\left(1-\frac{1}{9}\right)x\left(1-\frac{1}{10}\right)\)
\(=\frac{5}{6}x\frac{6}{7}x\frac{7}{8}x\frac{8}{9}x\frac{9}{10}\)
\(=\frac{1}{2}\)
=(1/1-1/6)x(1/1-1/7)x(1/1-1/8)x(1/1-19)x(1/1-1/10)
=5/6x6/6x7/8x8/9x9/10
a) \(5\times\left(3+7\times x\right)=400\)
\(3+7\times x=80\)
\(7\times x=77\)
\(x=11\)
b) \(x\times37+x\times63=1200\)
\(x\times\left(37+63\right)=1200\)
\(x\times100=1200\)
\(x=12\)
c) \(x\times6+12:3=40\)
\(x\times6+4=40\)
\(x\times6=36\)
\(x=6\)
d) \(4+6\times\left(x+1\right)=70\)
\(6\times\left(x+1\right)=66\)
\(x+1=11\)
\(x=10\)
e) \(163:x+34:x=10\)
\(\left(163+34\right):x=10\)
\(197:x=10\)
\(x=19,7\)
\(\dfrac{1}{2}\times\dfrac{2}{3}\times\dfrac{3}{4}\times\dfrac{4}{5}=\dfrac{1}{5}\)
\(a,\left(\frac{6}{11}+\frac{5}{11}\right)\times\frac{3}{7}\)
Cách 1: \(\left(\frac{6}{11}+\frac{5}{11}\right)\times\frac{3}{7}=1\times\frac{3}{7}=\frac{10}{7}\)
Cách 2: \(\left(\frac{6}{11}+\frac{5}{11}\right)\times\frac{3}{7}=\frac{6}{11}\times\frac{3}{7}+\frac{5}{11}\times\frac{3}{7}=\frac{18}{77}+\frac{15}{77}=\frac{33}{77}=\frac{3}{7}\)
\(b,\frac{3}{5}\times\frac{7}{9}+\frac{3}{5}\times\frac{2}{9}\)
Cách 1: \(\frac{3}{5}\times\frac{7}{9}+\frac{3}{5}\times\frac{2}{9}=\frac{7}{15}+\frac{2}{15}=\frac{9}{15}\)
Cách 2: \(\frac{3}{5}\times\frac{7}{9}+\frac{3}{5}\times\frac{2}{9}=\frac{3}{5}\times1=\frac{3}{5}\)
P/s: Ý B có vấn đề thì phải
\(a,\left(\frac{6}{11}+\frac{5}{11}\right)x\frac{3}{7}\)
\(=\frac{11}{11}=1x\frac{3}{7}\)
\(=\frac{3}{7}\)
cach 2
\(\frac{6}{11}x\frac{3}{7}+\frac{5}{11}x\frac{3}{7}\)
\(=\frac{18}{77}+\frac{15}{77}\)
\(=\frac{33}{77}=\frac{3}{7}\)
\(b,\frac{3}{5}x\frac{7}{9}+\frac{3}{5}x\frac{2}{9}\)
\(=\frac{21}{45}+\frac{6}{45}\)
\(=\frac{27}{45}=\frac{3}{5}\)
cách 2 :
\(\frac{3}{5}x\left(\frac{7}{9}+\frac{2}{9}\right)\)
\(=\frac{3}{5}x\frac{9}{9}\)
\(=\frac{27}{45}=\frac{3}{5}\)
\(\left(x+\frac{1}{2}\right)+\left(x+\frac{1}{4}\right)+\left(x+\frac{1}{8}\right)+\left(x+\frac{1}{16}\right)=\frac{23}{16}\)
\(4x+\frac{15}{16}=\frac{23}{16}\)
\(4x=\frac{1}{2}\)
\(x=\frac{1}{8}\)
Vậy \(x=\frac{1}{8}\)
\(\left(x+\frac{1}{2}\right)+\left(x+\frac{1}{4}\right)+\left(x+\frac{1}{8}\right)+\left(x+\frac{1}{16}\right)=\frac{23}{16}\)
\(\Rightarrow\left(x+x+x+x+x\right)+\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\right)=\frac{23}{16}\)
\(\Rightarrow5x+\frac{15}{32}=\frac{23}{16}\)
\(\Rightarrow5x=\frac{23}{16}-\frac{15}{32}\)
\(\Rightarrow5x=\frac{31}{32}\)
\(\Rightarrow x=\frac{31}{32}.\frac{1}{5}=\frac{31}{160}\)
\(x-\frac{4}{5}=\frac{4}{5}+\left(\frac{3}{7}+\frac{3}{5}\right)\)
\(x-\frac{4}{5}=\frac{4}{5}+\frac{36}{35}\)
\(x-\frac{4}{5}=\frac{64}{35}\)
\(x=\frac{64}{35}+\frac{4}{5}\)
\(x=\frac{92}{35}\)
\(x-\frac{4}{5}=\frac{4}{5}+\left(\frac{3}{7}+\frac{3}{5}\right)\)
\(x=\frac{4}{5}+\frac{3}{7}+\frac{3}{5}+\frac{4}{5}\)
\(x=\frac{11}{5}+\frac{3}{7}\)
\(x=\frac{11\times7+3\times5}{7\times5}\)
\(x=\frac{92}{35}\)
4.x+1/2.3+1/3.4+1/4.5+1/5.6=1
4.x+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6=1
4x+1-1/6=1
4x=1-5/6
4x=1/6
x=1/6:4
x=1/24
Chúc Học Tốt!!!
câu này ở trong Violympic nên mình nói luôn đáp án là 1/8