Tính hợp lí (nếu có thể): d) ( frac{{2 ,. ,{6^9} - {2^5} ,. ,{{18}^4}}}{{{2^2} ,. ,{6^8}}} ) ;

d) ( frac{{2 ,. ,{6^9} - {2^5} ,. ,{{18}^4}}}{{{2^2} ,. ,{6^8}}} ) [ = frac{{2 ,. ,{{ left( {2 ,. ,3} right)}^9} - {2^5} ,. ,{{ left( {2 ,. ,{3^2}} right)}^4}}}{{{2^2} ,. ,{{ left( {2 ,. ,3} right)}^8}}} ] [ = frac{{2 ,. ,{2^9} ,. ,{3^9} - {2^5} ,. ,{2^4} ,. ,{3^8}}}{{{2^2} ,. ,{2^8} ,. ,{3^8}}} ] [ = frac{{{2^{10}} ,. ,{3^9} - {2^9} ,. ,{3^8}}}{{{2^{10}} ,. ,{3^8}}} ] [ = frac{{{2^9} ,. ,{3^8} left( {6 - 1} right)}}{{{2^{10}} ,. ,{3^8}}} ]. [ = frac{5}{2} ]..

Tính hợp lí (nếu có thể): d) (2 . 6^ 9 − 2 ^5 . 18^ 4 )/(2^ 2 . 6^ 8) ;

Câu 1

Tính hợp lí (nếu có thể):

h) \(\frac{{11}}{{24}} - \frac{5}{{41}} + \frac{{13}}{{24}} + 0,5 - \frac{{36}}{{41}}\);

Xem đáp án

Lời giải

h) \(\frac{{11}}{{24}} - \frac{5}{{41}} + \frac{{13}}{{24}} + 0,5 - \frac{{36}}{{41}}\)

\( = \left( {\frac{{11}}{{24}} + \frac{{13}}{{24}}} \right) + 0,5 + \left( { - \frac{{36}}{{41}} - \frac{5}{{41}}} \right)\)

\( = 1 + 0,5 - 1 = 0,5\).

Câu 2

Tìm \(x\), biết:
i) \({\left( {x - \frac{2}{9}} \right)^3} = {\left( {\frac{2}{3}} \right)^6}\);

Xem đáp án

Lời giải

i) \({\left( {x - \frac{2}{9}} \right)^3} = {\left( {\frac{2}{3}} \right)^6}\)

\({\left( {x - \frac{2}{9}} \right)^3} = {\left( {\frac{4}{9}} \right)^3}\)

\(x - \frac{2}{9} = \frac{4}{9}\)

\(x = \frac{6}{9}\)

\(x = \frac{2}{3}\)

Vậy \(x = \frac{2}{3}\).

Câu 3