Question 669647
Hint:

The cost equation is C = 4.35x + 12000 (this is the cost to produce x units)


The revenue equation is R = 7.20x (this is how much you make -- excluding taxes, expenses, etc -- from selling x units)


The profit equation is 


P = R - C


P = 7.20x - (4.35x + 12000)


If you want to find the break even point, plug in P = 0 and solve for x.