7^x+2+2умножить на7^x-1=345

Question

7^x+2+2умножить на7^x-1=345

Answer 1

7 ^ ( Х + 2 ) + 2 • 7 ^ ( Х - 1 ) = 345
7 ^ x • ( 7 ^ 2 + 2 • ( 1/7 )) = 345
7 ^ 2 + 2 • ( 1/7 ) = 49 + ( 2/7 ) = 49 2/7 = 345/7
7 ^ x • ( 345/7 ) = 345
7 ^ x = 345 : ( 345/7 )
7 ^ x = 7
Х = 1