Question

7^х+2 + 4*7^х+1=539
Прошу, срочно

Answer 1

7^(х+2) + 4*7^(х+1)=539 
7^x*49 + 4*7*7^x = 539
7^x*49 + 7^x*28 = 539
7^x* ( 49 + 28) = 539
7^x * 77 = 77 * 7
7^x = 7 
x = 1