A) 47.35 + 65.47 - 699

= 47.(65 + 35) - 699

= 47.100 - 699

= 4700 - 699

= 4001 

B) 4.26.9 + 12.3.35 + 39.6.6

= 36.26 + 36.35 + 39.36

= 36.(26 + 35 + 39)

= 36.100

= 3600

\(3^x=3486784401\)

\(\Rightarrow3^x=3^{20}\)

\(\Rightarrow x=20\)

Vậy: x=20

A) \(150-100:\left(15\cdot6-40\right)\)

\(=150-100:\left(90-40\right)\)

\(=150-100:50\)

\(=150-2\)

\(=148\)

B) \(3\left(63-58\right)^2+2^7:2^4\cdot2^0\)

\(=3\cdot5^2+2^7:2^4\)

\(=3\cdot25+2^3\)

\(=75+8\)

\(=83\)

\(B=4x^2-12x+9\)

\(B=\left(2x\right)^2-2\cdot2x\cdot3+3^2\)

\(B=\left(2x-3\right)^2\)

Thay \(x=\dfrac{1}{2}\) vào B ta có: 

\(B=\left(2\cdot\dfrac{1}{2}-3\right)^2=4\)

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\(A=5\left(x+3\right)\left(x-3\right)+\left(2x+3\right)^2+\left(x-6\right)^2\)

\(A=5\left(x^2-9\right)+4x^2+12x+9+x^2-12x+36\)

\(A=5x^2-45+5x^2+45\)

\(A=10x^2\)

Thay \(x=\dfrac{1}{5}\)vào A ta có:

\(A=10\cdot\left(-\dfrac{1}{5}\right)^2=\dfrac{2}{5}\)

\(3x+15=5x+9\)

\(\Rightarrow5x-3x=15-9\)

\(\Rightarrow2x=6\)

\(\Rightarrow x=\dfrac{6}{2}\)

\(\Rightarrow x=3\)

Vậy: x=3

\(2^{x+22}-4^{x+11}=0\)

\(\Rightarrow2^{x+22}-2^{2x+22}=0\)

\(\Rightarrow2^x\cdot\left(2^{22}-2^{x+22}\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}2^x=0\left(L\right)\\2^{22}-2^{x+22}=0\end{matrix}\right.\)

\(\Rightarrow2^{x+22}=2^{22}\)

\(\Rightarrow x+22=22\)

\(\Rightarrow x=22-22\)

\(\Rightarrow x=0\)

Vậy x=0

\(5^{x+3}-5^{x+2}=62500\)

\(\Rightarrow5^x\cdot\left(5^3-5^2\right)=62500\)

\(\Rightarrow5^x\cdot\left(125-25\right)=62500\)

\(\Rightarrow5^x\cdot100=62500\)

\(\Rightarrow5^x=62500:100\)

\(\Rightarrow5^x=625\)

\(\Rightarrow5^x=5^4\)

\(\Rightarrow x=4\)

Vậy: x=4

\(5^{x+1}+5^x=30\)

\(\Rightarrow5^x\cdot\left(5+1\right)=30\)

\(\Rightarrow5^x\cdot6=30\)

\(\Rightarrow5^x=30:6\)

\(\Rightarrow5^x=5^1\)

\(\Rightarrow x=1\)

Vậy x=1

Chiều rộng hình chữ nhật là:

\(\dfrac{18}{4}:\dfrac{15}{4}=\dfrac{6}{5}\left(m\right)\)

Chu vi hình chữ nhật:

\(\left(\dfrac{6}{5}+\dfrac{15}{4}\right)\times2=\dfrac{99}{10}\left(m\right)\)

Đáp số:...

\(\dfrac{24}{48}-\dfrac{1}{3}\)

\(=\dfrac{1}{2}-\dfrac{1}{3}\)

\(=\dfrac{3}{6}-\dfrac{2}{6}\)

\(=\dfrac{1}{6}\)

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\(\left(\dfrac{3}{5}-\dfrac{1}{2}\right):\dfrac{3}{10}\)

\(=\left(\dfrac{6}{10}-\dfrac{5}{10}\right):\dfrac{3}{10}\)

\(=\dfrac{1}{10}:\dfrac{3}{10}\)

\(=\dfrac{1}{10}\times\dfrac{10}{3}\)

\(=\dfrac{1}{3}\)