Question

1.Tìm x, biết:

a. 2^x ; b. 5^x c. 3^x : 3⁵ d. \(\dfrac{16}{2^x}=2\) e. 8^x : 2^x f. 2^x . 3^x = 36 g. \(\dfrac{\left(-3\right)^n}{81}=-27\)

Answer 1

a. 2^x = 8 ; b. 5^x = 25 ; c. 3^x : 3⁵ = 9 d. \(\dfrac{16}{2^x}=2\) ; e. 8^x : 2^x = 4 ; f. 2^x . 3^x = 36 ; g. \(\dfrac{\left(-3\right)^n}{81}=-27\)

2^x = 2³ 5^x = 5² 3^x : 3⁵ = 3^{2 \(\dfrac{2^4}{2^x}=1\)} ( 2³)^x : 2^x = 2² 6^x = 6² \(\dfrac{\left(-3\right)^n}{\left(-3\right)^4}=\left(-3\right)^3\)

x = 3 x = 3 3^x = 3² . 3^{5 \(2^{4-x}=2^1\)} 2^3x : 2^x = 2² x = 2 \(\left(-3\right)^n=\left(-3\right)^3.\left(-3\right)^4\)

3^x = 3^{7 \(\Rightarrow4-x=1\)} 2^{3x - x} = 2² \(\left(-3\right)^n=\left(-7\right)^7\)

=>X = 7 x = 4 - 1 2^2x = 2² => n = 7

x = 3 2x = 2

x = 2 : 2

x = 1