The table below shows the proportional relationship between the weight of dog food, in ounces, and the number of bags of dog food: Number of Bags
of Dog Food Number of Ounces
of Dog Food
3
36
4
48
5
60

What is the constant of proportionality?
12
36
39
72

12

3×12=36

4×12=48

5×12=60

I hope this is good enough:

a and c

for infinitely many solutions we require both left and right sides to be equal

distribute and simplify

a

14 - 8x = 20 - 8x - 6 = 14 - 8x ← both sides equal so infinite solutions

b

6x - 54 = 6x - 54 + x = 7x - 54 ← not equal

c

4x + 16 = 4x + 10 + 6 = 4x + 16 ← both sides equal so infinite solutions

d

5x - 40 + 10 = 5x + 10

5x - 30 = 5x + 10 ← not equal