Question

Biết 2^{x + 2} - 2^x = 48. Vậy x là

Answer 1

2^{x + 2} - 2^x = 48

=> 2^x . 2² - 2^x = 48

=> 2^x (2² - 1) = 48

=> 2^x . 3 = 48

=> 2^x = 16

=> 2^x = 2⁴

=> x = 4

Answer 2

\(2^{x+2}-2^x=48\)

\(2^x.2^2-2^x=48\)

\(2^x.\left(2^2-1\right)=48\)

\(2^x.3=48\Leftrightarrow2^x=16\)

\(2^x=16=2^4\)

Vậy x = 4