Question

[Nguyễn Hồng Phúc An]

Chứng minh : \(\frac{\left(5^4-5^3\right)}{125^4}=\frac{64}{125}\)

Tìm x

a)\(^{3^x}+^{3^{x+2}}=810\)

b)\(\left(x+\frac{2017}{2018}\right)^6=0\)

Answer 1

[l҉o҉n҉g҉ d҉z҉]

Ta có : 3^x + 3^{x + 2} = 810

=> 3^x(1 + 3²) = 810

=> 3^x.10 = 810

=> 3^x = 81

=> 3^x = 3⁴

=> x = 4

Answer 2

[Bùi Đức Anh]

ta có \(3^3+3^x+2=810\)

=>\(3^x\left(1+3^2\right)=810\)

=>\(3^x.10=810\)

=>\(3^x=81\)

=>\(3^x=3^4\)

=>x=4

Vậy x=4