Answer:
y = (x / 100) + 100
Step-by-step explanation:
First, we need to know the amount of money that it spends on advertising for each extra unit sold. That would be equal to: 2,500 / 25 = 100
This value will be the divisor of the advertising expense (x) to obtain the variable factor of the number of units.
Since 100 units are already sold without investment, this value is taken as fixed and added.
And with the previous data, the formula remains:
y = (x / 100) + 100