tính
\(\left[\left(\frac{4}{3}\right)^{-2}.\left(\frac{3}{4}\right)^3\right]:\left(-\frac{2}{3}\right)^{-3}\)
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\(\frac{1}{99.97}-\frac{1}{97.95}-........-\frac{1}{5.3}-\frac{1}{3.1}\)
\(=-\left(-\frac{1}{99.97}+\frac{1}{97.95}+.........+\frac{1}{5.3}+\frac{1}{3.1}\right)\)
\(=-\left(-\frac{1}{99.97}+\frac{1}{97.95}+.......+\frac{1}{5.3}+\frac{1}{3.1}\right).\frac{2}{2}\)
\(=-\left(-\frac{2}{99.97}+\frac{2}{97.95}+......+\frac{2}{5.3}+\frac{2}{3.1}\right).\frac{1}{2}\)
\(=-\left(-\frac{1}{99}-\frac{1}{97}+\frac{1}{97}-\frac{1}{95}+.....+\frac{1}{5}-\frac{1}{3}+\frac{1}{3}-1\right).\frac{1}{2}\)
\(=\left(\frac{1}{99}-1\right).\frac{1}{2}\)
\(=-\frac{98}{99}.\frac{1}{2}\)
\(=-\frac{49}{99}\)
Vì S lớn hơn dãy số trên 2^3 lần(mỗi thừa số lớn hơn 2^3 lần)
Nên S = 3025x2^3=3025x8=24200
Vậy S = 24200
nha
\(\left[\left(0,15\right)^3\right]^0+\left[\left(\frac{1}{7}\right)^2\right]^{-1}.\left[\left(-2\right)^3\right]^2:2^5\)
\(=1+49.64:32\)
\(=1+98\)
\(=99\)
[ ( 0,15 )3 ]0 + [ ( 1/7 )2 ]-1 . [ ( -2 )3 ]2 : 25
= 1 + 49 . 64 : 32
= 1 + 98
= 99
Xét trường hợp:
\(3^{41}:5^{31}=\left(3^4:5^3\right)^{10}.\frac{3}{5}\)
Vậy \(3^4:5^3=\frac{81}{125}< 1\)
Mà \(\frac{3}{5}< 1\)
Vậy \(3^{41}:5^{31}< 1\)
Nên: \(5^{31}>3^{41}\)
ta có:
\(\frac{x-1}{2}=\frac{y-2}{3}=\frac{z-3}{4}\)
=> \(\frac{x-1}{2}=\frac{2y-4}{6}=\frac{3z-9}{12}\)và \(x-2y+3z=14\)
\(\frac{x-1}{2}=\frac{2y-4}{6}=\frac{3z-9}{12}=\frac{\left(x-1\right)-\left(2y-4\right)+\left(3z-9\right)}{2-6+12}\)
\(=\frac{x-1-2y-4+3z+9}{8}=\frac{14-1-4+9}{8}=\frac{18}{8}=\frac{9}{4}\)
+) \(\frac{x-1}{2}=\frac{9}{4}\)=> \(x-1=\frac{9}{2}\) => \(x=\frac{11}{2}\)
+) \(\frac{2y-4}{6}=\frac{9}{4}\)=> \(2y-4=\frac{27}{2}\)=> \(2y=\frac{35}{2}\)=> \(y=\frac{35}{4}\)
+) \(\frac{3z-9}{12}=\frac{9}{4}\)=> \(3z-9=27\)=> \(3z=36\)=> \(z=12\)
Vậy x=
y=
z=
\(x^2-4x=0\)
\(\Rightarrow x\left(x-4\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x=0\\x=4\end{cases}}\)
\(x^2-5x-6=0\)
\(\Leftrightarrow\left(x-6\right)\left(x+1\right)=0\)
\(\left[\left(\frac{4}{3}\right)^{-2}.\left(\frac{3}{4}\right)^3\right]:\left(-\frac{2}{3}\right)^{-3}\)
\(=\frac{9}{16}.\frac{27}{64}:\left(-\frac{27}{8}\right)\)
\(=-\frac{9}{128}\)
[(3/4)-2.(3/4)3]:(-2/3)-3
=[16/9.3/64]:9/4
=1/12:9/4
=1/27