câu b thôi nhé bạn
217+214=\(2^{14}x\left(2^3+1\right)\)=214 x 9 \(⋮\)9
=> \(\left(2^{17}+2^{14}\right)⋮9\)
a ) Ta có : \(15^3-25^2=\left(5.3\right)^3-\left(5^2\right)^2=5^3.3^3-5^{2.2}\)
\(=5^3.27-5^4=5^3.27-5^3.5=5^3.\left(27-5\right)=5^3.22\)
Vì \(22⋮11\Rightarrow5^3.22⋮11\Rightarrow\left(15^3-25^2\right)⋮11\)
Vậy \(\left(15^3-25^2\right)⋮11\)
b ) Ta có : \(2^{17}+2^{14}=2^{14}.2^3+2^{14}=2^{14}.8+2^{14}=2^{14}.\left(8+1\right)=2^{14}.9^{14}\)
nhầm
số 9^14 là số 9 nha bạn
nó là : \(2^{14}.\left(8+1\right)=2^{14}.9\)
Vì \(9⋮9\Rightarrow2^{14}.9⋮9\)\(\Rightarrow\)\(\left(2^{17}+2^{14}\right)⋮9\)
Vậy \(\left(2^{17}+2^{14}\right)⋮9\)
cả câu a nữa
153-252=\(5^3x3^3-5^4\)=\(5^3x\left(3^3-1\right)\)=\(5^3\) x 22 \(⋮\)11
