Respuesta :
Step-by-step explanation:
f(x) = 15(b)x
f(4) = 1215
15(b)4 = 1215
(15)(4)b = 1215
60b = 1215
60b / 60 = 1215 / 60
b = 20.25
Check the answer
15 * 20.25 * 4 = 1215
Answer:
3
Step-by-step explanation:
if you did this on prepworks its 3.
1215=15(b)4
121515=(b)4
81=b4
92=b4
(32)2=b4
34=b4
b = ±3