\(\frac{2}{3}\)+ \(\frac{2}{5}\): \(\frac{5}{4}\)
ghi cach lam cu the
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5/2 + 5/4 + 5/8 + 5/16 + 5/32 + 5/64
= 5(1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64)
Đặt A = 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64
=> 2A = 1 + 1/2 + 1/4 + 1/8 + 1/16 + 1/32
=> 2A - A = 1 - 1/64
=> A = 1 - 1/64
Do đó : 5(1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64) = 5(1 - 1/64) = 5 . 63/64 = 315/64
\(\frac{1}{2}.\left(\frac{1}{3}-\frac{1}{11}\right)\)
\(=\frac{1}{2}\times\frac{8}{33}\)
\(=\frac{4}{33}\)
*Cách làm làm trong ngoặc tròn trước rồi nhân :v
\(\frac{1}{2}\)x(\(\frac{1}{3}\)-\(\frac{1}{11}\))
=\(\frac{8}{66}\)
\(\frac{2}{7}-x=\frac{-3}{4}\)
\(x=\frac{2}{7}-\frac{-3}{4}\)
\(x=\frac{8}{28}+\frac{21}{28}=\frac{29}{28}\)
vậy \(x=\frac{29}{28}\)
chúc bn học tốt!
= 2/7- -3/4
= 8/28 + 21/28
= 29/28
vậy x =29/28
~Study Well~
tk mk nha
\(\frac{x+24}{1996}+\frac{x+25}{1995}+\frac{x+26}{1994}+\frac{x+27}{1993}+\frac{x+2036}{4}=0\)
\(\Leftrightarrow\frac{x+24}{1996}+1+\frac{x+25}{1995}+1+\frac{x+26}{1994}+\frac{x+27}{1993}+1+\frac{x+2036}{4}-4==0\)
\(\Leftrightarrow\frac{x+2020}{1996}+\frac{x+2020}{1995}+\frac{x+2020}{1994}+\frac{x+2020}{1993}+\frac{x+2020}{4}=0\)
\(\Leftrightarrow\left(x+2020\right)\left(\frac{1}{1996}+\frac{1}{1995}+\frac{1}{1994}+\frac{1}{1993}+\frac{1}{4}\right)=0\)
<=> x+2020=0 \(\left(\frac{1}{1996}+\frac{1}{1955}+\frac{1}{1994}+\frac{1}{1993}+\frac{1}{4}\right)=0\)
<=> x=-2020
=\(\frac{12}{16}+\frac{3}{16}+\frac{3}{16}\)
=\(\frac{18}{16}=\frac{9}{8}\)
a, \(\left(\frac{1}{5}-\frac{1}{4}\right)^2=\left(\frac{-1}{20}\right)^2=\frac{1}{400}\)
b, \(\left(\frac{5}{3}+\frac{1}{2}\right):\frac{-13}{5}+1\frac{5}{6}\)
=> \(\frac{13}{6}:\frac{-13}{5}+\frac{11}{6}\)
=> \(\frac{13}{6}.\frac{5}{-13}+\frac{11}{6}\)
=> \(\frac{-5}{6}+\frac{11}{6}=\frac{6}{6}=1\)
c, \(\left(\frac{3}{17}\right)^4.\left(\frac{-17}{6}\right)^4\)
=> \(\left(\frac{3}{17}.\frac{-17}{6}\right)^4=\left(\frac{-1}{2}\right)^4=\frac{1}{16}\)
Đặt A = \(\frac{1}{101}+\frac{1}{102}+\frac{1}{103}+...+\frac{1}{150}\)(50 số hạng)
=> A > \(\frac{1}{150}+\frac{1}{150}+\frac{1}{150}+...+\frac{1}{150}\)(50 số hạng)
=> A > \(\frac{1}{150}.50\)
=> A > \(\frac{1}{3}\)
=> \(\frac{1}{101}+\frac{1}{102}+\frac{1}{103}+...+\frac{1}{150}\) > \(\frac{1}{3}\)(Đpcm)
từ \(\frac{1}{101}\)đến \(\frac{1}{150}\)có 50 phân số.
có :\(\frac{1}{101}\)lớn hơn \(\frac{1}{150}\)
\(\frac{1}{102}\)lớn hơn \(\frac{1}{150}\)........cứ như vậy cho đến \(\frac{1}{149}\)lớn hơn \(\frac{1}{150}\).suy ra tổng 50 phân số đã cho lớn hơn 50 nhân vơi \(\frac{1}{150}\)=\(\frac{1}{3}\)
\(\frac{2}{3}+\frac{2}{5}\div\frac{5}{4}\)
\(=\frac{2}{3}+\frac{2}{5}\times\frac{4}{5}\)
\(=\frac{2}{3}+\frac{8}{25}\)
\(=\frac{74}{75}\)
~ Chúc bạn học tốt ~
nhanh len