X+1/10 + x+1/11 + x+1/12 = x+1/14 + x+1/15
\(B=\left|157\dfrac{13}{27}-273\dfrac{7}{19}\right|-96\dfrac{14}{27}+15\dfrac{12}{19}\)\(B=\left|157\dfrac{13}{27}-273\dfrac{7}{19}\right|-96\dfrac{14}{27}+15\dfrac{12}{19}\)
Tính bằng cách hợp lí :
a , \(\dfrac{1}{15}+\dfrac{9}{10}+\dfrac{14}{15}-\dfrac{11}{9}-\dfrac{20}{10}+\dfrac{1}{157}\)
b , \(\dfrac{1}{5}-\dfrac{-1}{3}+\dfrac{-1}{5}-\dfrac{2}{6}\)
c , \(\dfrac{2}{1\times3}+\dfrac{2}{3\times5}+...+\dfrac{2}{2015\times2017}\)
d , \(\dfrac{5}{1\times3}+\dfrac{5}{3\times5}+...+\dfrac{5}{2015\times2017}\)
e , \(\dfrac{1}{1\times2}+\dfrac{1}{3\times4}+...+\dfrac{1}{2016\times2017}\)
chứng minh rằng không tồn tại 3 số hữu tỉ a, b, c sao cho; ab=13/15; bc=11/3; ac=-3/13
\(\dfrac{-15}{4}\).\((-\dfrac{16}{25})\)
15.\(-(\dfrac{13}{10})\)
\((-\dfrac{14}{5})\).(-10)
\((\dfrac{3}{-10})\).-\((\dfrac{-15}{2})\)
so sánh
a)9^20......27^13
b)2^21.......3^14
Tính Nhanh:68 x 15 - 18/68 x 14 +50
thức hiện hiện mỗi phép tính sau bằng hai cách
a)\(3\dfrac{4}{9}+5\dfrac{1}{6}\), b,\(8\dfrac{1}{14}-6\dfrac{3}{7}\) c,\(7-3\dfrac{6}{7}\)
1.Rút gọn :
(x-1)^2-(x+4)(x-4)
2. Tìm x:
3(2x-4)+15=-11
x(x+2)-3x-6=0
