Viết tích ${9^3}{.27^2}.81\;$ dưới dạng lũy thừa của $3$, ta được:

\(\left\{ {0;1;2;3;4} \right\}\)                 

\(\left\{ {6;7;8;9;10} \right\}\)             

\(\left\{ {1;2;3;4} \right\}\)                     

\(\left\{ {1;2;3;4;5} \right\}\)

$7$ 

$15$ 

$12$ 

$17$

\({7^4}{.7^3} = {7^{12}}\) 

\({7^4}{.7^3} = {1^1}\)

\({7^4}{.7^3} = {14^7}\)

\({7^4}{.7^3} = {7^7}\)

\({x^4}\)

\({x^6}\)

\(x\)

\({x^{10}}\)

 \(10000 = {10^3}\)

\({1020^0} = 0\)

\(x.{x^7} = {x^7}\)

\({12^7}:{12^4} = {12^3}\)

$47$ 

$48$

$50$

$51$

\(A = \left\{ {15;30;45} \right\}\)

\(A = \left\{ {10,20,30,40} \right\}\)

\(A = \left\{ {15,25,35,45} \right\}\)

\(A = \left\{ {15,30,45,46} \right\}\)