2. The set of all first coordinates is called
a. domain
b. range
c. slope
d. axis

a. domain

Step-by-step explanation:

The domain is the set of all first elements of ordered pairs (x-coordinates)

The set of all first coordinates is called DOMAIN

$53.50

step-by-step explanation:

you have to subtract the amount of money chuck earned ($72.50) by the cost of the gas for the mower ($11.25) and the new string for the trimmer he bought ($7.75).

72.50-11.25=61.25

and then subtract $61.25 by the second thing he bought (the new string for the trimmer)

61.25-7.75=53.5

so in total it's $53.50 (53 dollars and 50 cents)