I think I wrote this wrong because I needed to enter a formula calculate the break-even point C18, which is determined by the fixed monthly expense C17 divided by the difference between the price per unit C15 and the number of units G15:G43. Then to Use the IFERROR function to display a blank cell.
I changed the function to this one below but the cell is not blank it has a 0.
Is this the correct way to write the function?

=IFERROR(VLOOKUP(C18,C17/C15/G15:G43,2,FALSE),"")