Tính: a) 72^3/24^3 b) (-10,5)^3/(3,5)^3 c) 15^3/27 d) (0,125)^3 . 8^3 e) (-39)^4 : (13)^4 25/07/2021 Bởi Madelyn Tính: a) 72^3/24^3 b) (-10,5)^3/(3,5)^3 c) 15^3/27 d) (0,125)^3 . 8^3 e) (-39)^4 : (13)^4
Đáp án: $a)27;b) – 27;c)125;d)1;e)81$ Giải thích các bước giải: $\begin{array}{l}a)\dfrac{{{{72}^3}}}{{{{24}^3}}} = {\left( {\dfrac{{72}}{{24}}} \right)^3} = {3^3} = 27\\b)\dfrac{{{{\left( { – 10,5} \right)}^3}}}{{{{\left( {3,5} \right)}^3}}} = {\left( {\dfrac{{ – 10,5}}{{3,5}}} \right)^3} = {\left( { – 3} \right)^3} = – 27\\c)\dfrac{{{{15}^3}}}{{27}} = \dfrac{{{{15}^3}}}{{{3^3}}} = {\left( {\dfrac{{15}}{3}} \right)^3} = {5^3} = 125\\d)0,{125^3}{.8^3} = {\left( {0,125.8} \right)^3} = {1^3} = 1\\e){\left( { – 39} \right)^4}:{13^4} = {\left( {\dfrac{{ – 39}}{{13}}} \right)^4} = {\left( { – 3} \right)^4} = 81\end{array}$ Bình luận
Đáp án:
$a)27;b) – 27;c)125;d)1;e)81$
Giải thích các bước giải:
$\begin{array}{l}
a)\dfrac{{{{72}^3}}}{{{{24}^3}}} = {\left( {\dfrac{{72}}{{24}}} \right)^3} = {3^3} = 27\\
b)\dfrac{{{{\left( { – 10,5} \right)}^3}}}{{{{\left( {3,5} \right)}^3}}} = {\left( {\dfrac{{ – 10,5}}{{3,5}}} \right)^3} = {\left( { – 3} \right)^3} = – 27\\
c)\dfrac{{{{15}^3}}}{{27}} = \dfrac{{{{15}^3}}}{{{3^3}}} = {\left( {\dfrac{{15}}{3}} \right)^3} = {5^3} = 125\\
d)0,{125^3}{.8^3} = {\left( {0,125.8} \right)^3} = {1^3} = 1\\
e){\left( { – 39} \right)^4}:{13^4} = {\left( {\dfrac{{ – 39}}{{13}}} \right)^4} = {\left( { – 3} \right)^4} = 81
\end{array}$