求助TTGWD3-6

hedongshi

If x and k are integers and (12^x)(4^2x+1) = (2^k)(3²), what is the value of k?

 

A.     5

B.     7

C.     10

D.     12

E.      14

K是怎末求出来的呀?谢谢帮助:-)

Jarod

能错吗？！

sunjueliang

(12^x)(4^2x+1) = (2^k)(3²)

等式左边划成: (2^2x3^x)(2^2(2x+1)) =>(2^6x+2) (3^x)=> 6x+2=K, 试算: x=1,2...

得x=2, k=14, 选E

不知对否?