Let f(x)=6−1x+15x2. Calculate the following values:

Question

f(a)=  

f(a+h)=  

f(a+h)−f(a)/h=

for h≠0

Answer 1

Given: f(x) = 15x^2 -x + 6

Then f(a) = 15a^2 - a + 6

And f(a+h) = 15(a+h)^2 - (a+h) + 6

So ( f(a+h) - f(a) ) / h is then a big mess, but 6 terms cancel each other and drop out. It's easy to make a mistake, but here's the answer that I got:

30a + 15h -1