The number of units of x that must be sold to break even is 12 units.
Explanation:
It is given that the cost function C(x) is given by
[tex]C(x)=9000 x+72,000[/tex]
Also, the revenue function R(x) is given by
[tex]R(x)=15,000 x[/tex]
The break even point can be determined by equating the cost function and the revenue function.
Thus, we have,
[tex]15,000 x=9000x+72000[/tex]
Subtracting both sides by [tex]9000x[/tex] , we get,
[tex]6000x=72000[/tex]
Dividing both sides by [tex]6000[/tex] , we have,
[tex]x=12[/tex]
Thus, it takes 12 units to be sold to break even.
Hence, the number of units of x that must be sold to break even is 12 units.