Complete question is;
In an exponential function, f(x) = a(b)^x, it is known that f(5) = 15 and f(7) = 170. which of the following is closest to the value of b?
Answer:
b = 3.37
Explanation:
The function given is f(x) = a(b)^x,
Now, f(5) = 15, Thus;
15 = a(b)^(5)
Also, f(7) = 170
Thus; 170 = a(b)^(7)
From first equation, a = 15/(b)^(5))
Putting this in second equation;
170 = (15/(b)^(5))) × (b)^(7)
170 = 15b²
b² = 170/15
b² = 11.333
b = √11.333
b = 3.37