Let x be the number of timers produced and sold.
Cost = 8x + 48,000
Revenue = 14x
Both graph as straight lines. Break-even point is where they intersect. To find the break-even point algebraically, set Revenue = Cost and solve for x.
Profit = Revenue - Cost = 14x - (8x + 48,000) = 6x - 48,000
Profit graphs as a straight line as well. It crosses the x-axis when Profit = 0. Set Profit = 0 and solve for x. It is also the break-even point.