Answer:
100 units.
Step-by-step explanation:
I am assuming that C is the cost.
You Can form the quadratic equation: 10530=x^2+5x+30. You put the left side to zero by subtracting 10530: x^2+5x+30-10530=0. You will get that x^2+5x-10500. You can use the quadratic formula or factoring. The factors that multiply to 10530 and add up to 5 is 105 and -100. You group: (x+105)(x-100)=0, you then use the zero-product property: x+105=0, x-100=0.
you get that x=100, -105. The number of units cant be negative, so x must be 100.
