Answer: 11 units must be sold to break even.
Explanation:
Profit is expressed as Revenue - Cost. Break even is the point at which there is neither profit nor loss. This means that profit would be zero. Therefore,
Revenue - cost = 0
Revenue = cost
Given the cost function, C(x) to be
C(x) = 4000x + 88,000
and the revenue function, R(x) to be
R(x) = 12,000x, the number of units x that must be sold to break even would be
4000x + 88000 = 12000x
12000x - 4000x = 88000
8000x = 88000
x = 88000/8000 = 11