solve for x
a) 9^x+1=3^4x+5
b) 7^x=25
a) I will assume you meant
9^(x+1) = 3^(4x+5)
those brackets are essential
(3^2)^(x+1) = 3^(4x+5)
3^(2x+2 = 3^(4x+5)
then 2x+2 = 4x+5
2x + -3
x = -3/2
In the second we cannot use that method, since we can't easily change base 7 to base 25 or even 5
so ... take log of both sides
log 7^x = log 25
x log7 = log25
x = log25/log7 = appr 1.6542
check : 7^ 1.65412 = 24.997.. (not bad)