Question

The number N in millions of hearing impaired individuals of age x can be approximated by N=-0.00006x^3+0.006x^2-0.1x+1.2. Approxiamate to the nearest million the number of hearing impaired individuals of ages 50 and 75.

Answer 1

Lizzy,

Again you have a function with a variable (just one this time). You are asked to approximate to the nearest million of individuals ages 50 and 75, which just means "calculate this function for the variables x=50 and x=75".

So you have to do two calculations, one where you substitute x for 50 in your function and calculate the answer and one where you substitute x for 75.

The first is (x=50):
N = 0.00006 * 50^3 + 0.006 * 50² - 0.1 * 50 + 1.2 = ... (calculate)

I think you can do the second one by yourself.