Answer:

Step-by-step explanation:

Let's solve one of them for x.

Add 4

Divide by 3.

Now, plug the value of y in the formula, or you can plug the value of x in the other equation. I'll take this one.




Multiply by 3 to get rid of the denominator.

add x

Combine like terms;

Divide by 4.

Simplify.

Now that you found the value of x, replace it in any of the equations to find y.


Proof:




Answer:
its c)
Step-by-step explanation:
just looked it up
The cost function is
c = 0.000015x² - 0.03x + 35
where x = number of tires.
To find the value of x that minimizes cost, the derivative of c with respect to x should be zero. Therefore
0.000015*2x - 0.03 = 0
0.00003x = 0.03
x = 1000
Note:
The second derivative of c with respect to x is positive (= 0.00003), so the value for x will yield the minimum value.
The minimum cost is
Cmin = 0.000015*1000² - 0.03*1000 + 35
= 20
Answer:
Number of tires = 1000
Minimum cost = 20