=>1,3x-15=-3:5/14=-3*2,8=-8,4
=>1,3x=6,6
=>x=66/13
Tuyển Cộng tác viên Hoc24 nhiệm kì 26 tại đây: https://forms.gle/dK3zGK3LHFrgvTkJ6
=>1,3x-15=-3:5/14=-3*2,8=-8,4
=>1,3x=6,6
=>x=66/13
Tìm x biết: \(\dfrac{13}{14}+\dfrac{13}{35}+\dfrac{13}{65}+\dfrac{13}{104}+...+\dfrac{13}{1274}-x+2\dfrac{1}{5}=0\)
a)Tìm số nguyên sao cho 4n-5 chia hết cho n-3
b)Chứng minh rằng:
S=\(\dfrac{1}{5}+\dfrac{1}{13}+\dfrac{1}{14}+\dfrac{1}{15}+\dfrac{1}{61}+\dfrac{1}{62}+\dfrac{1}{63}< \dfrac{1}{2}\)
Chứng tỏ rằng:
\(\dfrac{1}{5}+\dfrac{1}{13}+\dfrac{1}{14}+\dfrac{1}{15}+\dfrac{1}{61}+\dfrac{1}{62}+\dfrac{1}{63}< \dfrac{1}{2}\)
Tính hợp lý :
a,\(\left(\dfrac{136}{15}-\dfrac{28}{5}+\dfrac{62}{10}\right).\dfrac{21}{24}\)
b,\(\dfrac{3}{11}.\dfrac{4}{11}+\left(\dfrac{3}{13}.\dfrac{4}{11}-\dfrac{1}{13}\right)\)
Chứng minh rằng P>3 biet P= \(\dfrac{5}{2×1}+\dfrac{4}{1×11}+\dfrac{3}{11×2}+\dfrac{1}{2×15}+\dfrac{13}{15×4}+\dfrac{15}{4×43}+\dfrac{13}{43×8}\)
Hãy chọn cặp gồm hai phân số bằng nhau.
\(\dfrac{15}{-10}\) và \(\dfrac{5}{4}\)
\(\dfrac{-3}{2}\) và \(\dfrac{2}{-3}\)
\(\dfrac{2}{-3}\) và \(\dfrac{-15}{-12}\)
\(\dfrac{15}{-10}\) và \(\dfrac{-3}{2}\)
1. thực hiện phép tính
a. \(\dfrac{11}{21}\)+\(\dfrac{-4}{7}\)
b. \(\dfrac{5}{15}\)+\(\dfrac{14}{25}\)-\(\dfrac{12}{9}\)+\(\dfrac{2}{7}\)+\(\dfrac{11}{25}\)
c. \(\dfrac{2}{3}\)+\(\dfrac{5}{7}\)-\(\dfrac{3}{14}\)
d. \(\dfrac{2}{5}\)-\(\dfrac{3}{7}\)+\(\dfrac{9}{45}\)
e.\(\dfrac{21}{47}\)+\(\dfrac{9}{45}\)+\(\dfrac{26}{47}\)+\(\dfrac{45}{5}\)
f. \(\dfrac{15}{12}\)-\(\dfrac{18}{13}\)+\(\dfrac{5}{13}\)-\(\dfrac{3}{12}\)
g. \(\dfrac{-8}{18}\)-\(\dfrac{15}{27}\)
h.\(\dfrac{3}{7}\)+\(\dfrac{-5}{2}\)-\(\dfrac{3}{5}\)
i.(\(\dfrac{11}{12}\):\(\dfrac{33}{16}\)).\(\dfrac{3}{5}\)
tìm x thuộc Z
a,\(\dfrac{-5}{6}\) . \(\dfrac{120}{25}\) < x< \(\dfrac{-7}{15}\) . \(\dfrac{9}{14}\)
b, (\(\dfrac{-5}{3}\))3 < x < \(\dfrac{-24}{35}\) . \(\dfrac{-5}{6}\)
câu 9
a)\(\dfrac{x+2}{14}\)=\(\dfrac{-1}{2}\);
b)\(\dfrac{x-1}{15}\)=\(\dfrac{4}{20}\);
c)\(\dfrac{x-7}{12}\)=\(\dfrac{-12}{16}\).
câu 10
a)\(\dfrac{x}{7}\)=\(\dfrac{x+1}{14}\);
b)\(\dfrac{2x+5}{3}\)=\(\dfrac{-4}{12}\).
ai cố giúp mình 2 bai đi