this is a function becuase it passes the verticle line test (no 2 points are above each other).
Answer:
Let the Dulcina's collection be 'x'
Let the Tremaine collection be 'x-39'
x + x - 39 =129
2x = 129 +39
2x = 168
x = 168/2
x = 84
Dulcina's collection = x = 84
Tremaine's collection = x - 39 = 84 - 39 = 45
3x=4y
x+y=21
x = 21-y
3(21-y)=4y
63-3y=4y
63=7y
y=9
x+y=21
x+9=21
x=12
answer is (12, 9)
Perimeter: 2l+2w=P
Plug in: 2(35)+3(22)=P
Solve: 70+66=136
The total perimeter of his yard is 136 feet.
Half times $7.25: 136/2=68(7.25)=493
The total cost for half his yard is $493 :)
