Acompany manufactures replacement parts for construction cranes. the fixed manufacturing cost is $2,400 and the variable cost per part is $5.50. each part is sold at $8.50.
the minimum number of parts the company must sell to break even

The cost to the company =
$5.50 per part for x parts
$2,400 manufacturing
The money earned by the company =
$8.80 per part for x parts
For break even situation, the earnings must equal the cost:
8.80x = 5.50x + 2400
3.30x = 2400
x = 727.27
The company must sell 728 parts to break even (because 0.27 part cannot be sold)

B. because the 7 represents "seven times", x represents "a number", 12 represents "plus twelve", and -4 represents "minus four"