. Bài tập - Chủ đề 1: Số hữu tỉĐơn giản các biểu thức sau:
\(\eqalign{ & a)\,\,{{{2^3}{{.2}^4}} \over {{2^5}}} \cr & b)\,\,{{{{\left( {0,2} \right)}^5}.{{\left( {0,6} \right)}^4}} \over {{{\left( {0,2} \right)}^7}.{{\left( {0,3} \right)}^4}}} \cr & c)\,\,{{{3^3}{{.12}^4}} \over {{6^5}{{.9}^4}}} \cr & d)\,\,{{{2^3} + {2^4} + {2^5}} \over {{7^2}}} \cr & e)\,\,{{{2^{15}}{{.9}^4}} \over {{6^6}{{.8}^3}}} \cr} \)
\(\eqalign{ & a){{{2^3}{{.2}^4}} \over {{2^5}}} = {{{2^7}} \over {{2^5}}} = {2^2} = 4 \cr & b){{{{(0,2)}^5}.{{(0,6)}^4}} \over {{{(0,2)}^7}.{{(0,3)}^4}}} = {{{{(0,2)}^5}.{{(0,3.2)}^4}} \over {{{(0,2)}^7}.{{(0,3)}^4}}} = {{{{(0,2)}^5}.{{(0,3)}^4}{{.2}^4}} \over {{{(0,2)}^7}.{{(0,3)}^4}}} = {{{{1.1.2}^4}} \over {{{(0,2)}^2}.1}} = {{16} \over {0,04}} = 400 \cr & c){{{3^3}{{.12}^4}} \over {{6^5}{{.9}^4}}} = {{{3^3}.{{(3.4)}^4}} \over {{{(2.3)}^5}.{{({3^2})}^4}}} = {{{3^3}{{.3}^4}.{{({2^2})}^4}} \over {{2^5}{{.3}^5}{{.3}^8}}} = {{{2^8}{{.3}^7}} \over {{2^5}{{.3}^{13}}}} = {{{2^3}} \over {{3^6}}} = {{{2^3}} \over {{{({3^2})}^3}}} = {\left( {{2 \over 9}} \right)^3} \cr & d){{{2^3} + {2^4} + {2^5}} \over {{7^2}}} = {{{2^3}.1 + {2^3}.2 + {2^3}{{.2}^2}} \over {{7^2}}} = {{{2^3}.(1 + 2 + {2^3})} \over {{7^2}}} = {{8.7} \over {7.7}} = {8 \over 7} \cr & e){{{2^{15}}{{.9}^4}} \over {{6^6}{{.8}^3}}} = {{{2^{15}}.{{({3^2})}^4}} \over {{{(2.3)}^6}.{{({2^3})}^3}}} = {{{2^{15}}{{.3}^8}} \over {{2^6}{{.3}^6}{{.2}^9}}} = {{{2^{15}}{{.3}^8}} \over {{2^{15}}{{.3}^6}}} = {3^2} = 9 \cr} \)