Question

if the cost, C, for manufacturing x units of a certain product is given by C=x^2-5x+70, find the number of units manufactured at a cost of $8620

Answer 1

well \(C(x)=x^2-5x+70\) and you know the cost is $8620 so \[x^2-5x+70=8620\]now solve for x. Do you know how to do that?

Answer 2

no, that is where I'm having the problem cause I don't understand algebra

Answer 3

quadratic formula, where a = 1, b= 5, c = -8550

Answer 4

b = -5 sorry

Answer 5

alright well the first thing you usually want to do is write this in general form. To do this you subtract 8620 from both sides

Answer 6

I have no idea what you are talking about

Answer 7

\[x^2-5x+70-8620=0\]\[x^2-5x-8850=0\]Now you want to find the roots to that. First you want to see if it can be factored, if it can then that's great and if not you need to use the quadratic formuala.

Answer 8

i'm getting there!

Answer 9

ok

Answer 10

the quadratic formula finds the roots of quadratic polynomials.

For a quadratic polynomial in general form, that is \(f(x)=ax^2+bx+c=0\), the quadratic formulas is \[\frac{-b\pm\sqrt{b^2-4ac}}{2a}\]