D.
y=2x+5
Sub in one pair (5,15)
15=2(5)+5
15=10+5
15=15 [Correct]
AND
9=2(2)+5
9=4+5
9=9 [Correct]
You said that Y = Mx + B
Subtract B from each side: Y - B = Mx
Divide each side by 'x' : (Y - B) / x = M
Well it would take 25 packages of 12 hotdogs because you have to divide 300 by 12 and 37 and a half buns
The number is 7 because of the transitive property of addition