Question

jennifer has a taco stand. she has found that her daily costs can be modeled by c(x)=x^2-40x+610, where c(x) is the cost, in dollars, to sell x units of taco. if she wants to keep her daily costs at $300, how many units of tacos does she need to sell?

Answer 1

C(x) = 300.

Our question becomes simple: 300 = x^2-40x+610

x^2-40x+610-300 = 0
x^2-40x+310 = 0

Now find the value for x with either the quadratic formula or by factorization.

Let me know how it goes. Giving the full answer won’t help you improve

Answer 2

C(X)=x^2-40x+610
300=X^2-40X+610
300-300=X^2-40x+610-300
X^2-40X+300=0

-b +- √b^2-4ac/2a
-(-40) +√-40^2-4(1)(310)/2(1)
40+√1600-1240/2
40+√360/2
x=29.48 or 29
-b +- √b^2-4ac/2a
-(-40) -√-40^2-4(1)(310)/2(1)
40-√1600-1240/2
40-√360/2
x=10.51 or 11