1% của 256 là 256:100=2,56

64 chiếm số % là: 64:2,56=25%

25%, ( đúng 100% đó bạn)

duyệt đi

ket qua = 25% ban nha

\(=\dfrac{64^2+256^2}{256^2+1024^2}=\dfrac{64^2\left(1+4^2\right)}{256^2\left(1+4^2\right)}=\left(\dfrac{64}{256}\right)^2=\dfrac{1}{16}\)

các bạn ơi giúp mình với , mình cần gấp lắm

Mình chỉ biết là ra 1/16 thôi

A=39760. b=158692,1211

\(P=\dfrac{1}{256}+\dfrac{1}{128}+...+1\)

\(=1+\dfrac{1}{2}+\left(\dfrac{1}{2}\right)^2+...+\left(\dfrac{1}{2}\right)^8\)

=>\(2P=2+1+\dfrac{1}{2}+...+\left(\dfrac{1}{2}\right)^7\)

=>\(2P-P=2+1+\dfrac{1}{2}+...+\left(\dfrac{1}{2}\right)^7-1-\dfrac{1}{2}-\left(\dfrac{1}{2}\right)^2-...-\left(\dfrac{1}{2}\right)^8\)

=>\(P=2-\left(\dfrac{1}{2}\right)^8=\dfrac{511}{256}\)

a) \(64^x:16^x=256\)

\(\Rightarrow\left(2^6\right)^x:\left(2^4\right)^x=2^8\)

\(\Rightarrow2^{6x}:2^{4x}=2^8\)

\(\Rightarrow2^{6x-4x}=2^8\)

\(\Rightarrow2^{2x}=2^8\)

\(\Rightarrow2x=8\)

\(\Rightarrow x=4\)

b) \(\dfrac{-2401}{7^x}=-7\)

\(\Rightarrow\dfrac{-7^4}{7^x}=-7\)

\(\Rightarrow-7^{4-x}=-7\)

\(\Rightarrow7^{4-x}=7\)

\(\Rightarrow4-x=1\)

\(\Rightarrow x=4-1\)

\(\Rightarrow x=3\)

c) \(\dfrac{64}{\left(-4\right)^x}=-256\)

\(\Rightarrow\left(-4\right)^x=\dfrac{64}{-256}\)

\(\Rightarrow\left(-4\right)^x=-4\)

\(\Rightarrow\left(-4\right)^x=\left(-4\right)^1\)

\(\Rightarrow x=1\)

\(a) 64^x:16^x=256\\\Rightarrow (64:16)^x=256\\\Rightarrow 4^x=4^4\\\Rightarrow x=4\\---\)

\(b,\dfrac{-2401}{7^x}=-7\)

\(\Rightarrow7^x=-2401:\left(-7\right)\)

\(\Rightarrow7^x=343\)

\(\Rightarrow7^x=7^3\)

\(\Rightarrow x=3\)

\(c,\dfrac{64}{\left(-4\right)^x}=-256\)

\(\Rightarrow\left(-4\right)^x=64:\left(-256\right)\)

\(\Rightarrow\left(-4\right)^x=-\dfrac{1}{4}\)

\(\Rightarrow\left(-4\right)^x=\left(-4\right)^{-1}\)

\(\Rightarrow x=-1\)

#\(Toru\)

64\(^x\) : 16\(^x\) = 256

(64: 16)^\(x\)  = 256

        4\(^x\)  = 4⁴

          \(x\) = 4

Vậy \(x\) = 4

(64 x 64 +256 x 256)/ (256 x 256 + 1024 x 1024)

= (64 x 64 + 64 x4 x 64 x 4)/(256 x 256 + 256 x4 x 256 x4)

= [64 x 64(1+4 x4 )]/[256 x 256(1+ 4x4)]

=64 x 64 /256 x 256

= 64 x 64 / 64 x4 x 64 x4  

= 1/16

\(\frac{\text{(64 x 64 +256 x 256)}}{\text{(256 x 256 + 1024 x 1024) }}\)

= \(\frac{\text{(64 x 64 + 64 x4 x 64 x 4)}}{\text{(256 x 256 + 256 x4 x 256 x4) }}\)

= \(\frac{\text{[64 x 64(1+4 x4 )]}}{\text{[256 x 256(1+ 4x4)] }}\)

=\(\frac{\text{64 x 64}}{\text{256 x 256 }}\) 

= \(\frac{\text{ 64 x 64 }}{\text{64 x4 x 64 x4 }}\)

= \(\frac{1}{\text{16}}\)

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