We need the exponents law
So if
a=3
b=1/2
then
where x represent every half a year.
The generic equation for a linear function can be expressed in the slope intercept form f(x) = mx + b, where m is the slope and b is the y intercept. For this problem we can first find the equation of the line. Then we substitute x = 7 to get the f(x) value, which is n at the point x = 7.
To find the equation of the linear function we first find the slope. Slope is defined as the change in f(x) divided by the change in x. As we are given a linear function, the slope at every point is the same. We can pick any two points known to find the slope.
Let's pick (3, 7) and (9, 16). The slope m is m = (16-7)/(9-3) = 9/6 = 3/2.
Now that we have the slope, we can plug in the slope and one of the points to find b. Let's use the point (3, 7).
f(x) = mx + b
7 = (1/2)(3) + b
b = 11/2
Now we can write the equation
f(x) = (1/2)x + 11/2
Plugging in x = 7 we find that f(7) = 9. n = 9
