Idon't understnad this .
*d • r = r • d ? ?
a.)commutative property of multiplication
b.)identity property of multiplication
c.)zero property of multiplication
d.)commutative property of addition

This is really easy this are property you can look it up on google

$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)