Question

7^x+7^x-1+7^x-2=38
Решите плиз

Answer 1

49x+49x+49x=41
147x=41
x=41/147

Answer 2

откуда 49?

Answer 3

7^x+7^(x-1)+7^(x-2)=38

7^x(1+1/7+1/49)=38
7^x (49+7+1)=38*49

7^x= 38*49/57

7^x=2*49/3
x=log(7)49+log(7)2/3=2+log(7)2/3