# Math Help - Two problems, help please

1. ## Two problems, help please

I have two problems that I can't figure out.

1.) if f(x) = 3x^2 - x +c and f(3) = 18, What is the value of C?

2.) if f(x) = 2x+5/X-A and f(0) = -1, what is the Value of A?

2. Originally Posted by MathMack
I have two problems that I can't figure out.

1.) if f(x) = 3x^2 - x +c and f(3) = 18, What is the value of C?

2.) if f(x) = 2x+5/X-A and f(0) = -1, what is the Value of A?

I'll show you how to solve the first problem and leave the second for you:

1. f(3) means that you should plug in the value 3 instead of x:

$f(3)=3\cdot (3)^2-3+c=18$

2. Collect all constants at the RHS and you're done. I've got c = -6