Answer:
( ln((d + c) / a) ) / ( ln(b) )
Step-by-step explanation:
ab^x = d + c
b^x = (d + c) / a
ln(b^x) = ln((d + c) / a)
xln(b) = ln((d + c) / a)
x = ( ln((d + c) / a) ) / ( ln(b) )