Given that,
Total cost function, C (x) = 43x + $1850
The revenue function R (x) = $80x
To find,
The number of units that must be produced and sold to break even.
Solution,
At break even, cost = revenue
43x + $1850 = $80x
Subtract 80x from both sides.
43x + 1850 -80x = $80x -80x
1850 = 80x-43x
37x = 1850
x = 50
So, the required number of units are 50.