Question

2.3^x+3^x-1=7.(3²+2.6²⁾

7^x+22.7^x-1=345

Answer 1

2.3^x + 3^{x - 1} = 7 . (3² + 2 . 6²)

=> 2.3^x + 3^{x - 1} = 567

=> 7 . 3^{x - 1} = 567

=> 3^{x - 1} = 567 : 7 = 81

=> x - 1 = 4

=> x = 5

Answer 2

a)2*3^x+3^x-1=7(3²+2*6²)

2*3^x+3^x-1=7(9+72)=7*81

2*3^x+3^x/3=567

2*3^x+3^x*1/3=567

(2+1/3)*3^x=567

7/3*3^x=567

3^x=567:7/3

3^x=243=3⁵

=>x=5

b) mk ko hiểu đề mấy, cái chỗ 7^x+2 là nhân vs 2 ak