Diketahui persamaan [tex]y=nx^m-4[/tex]. Nilai y=8 saat x=2 dan y=71 saat x=5. Tentukan nilai m dan n!

jawab

y = n x^m

y = 8 , x= 2 → 8 = n (2)^m - 4 → n (2)^m = 8+4
n= (12)/(2^m)

y = 71 ,x= 5 → 71 = n (5)^m - 4 → n(5)^m = 71+4
n = 75/ (5^m)

12/ 2^m = 75/5^m
5^m/2^m = 75/12
(5/2)^m = (25/4)= (5/2)²
m = 2

n = 12/(2^m)
n = 12 / (2^2)
n = 12/4
n = 3