D. Equivalent is the answer
Answer:
B represents a function.
Step-by-step explanation:
Recall these characteristics of a "function:"
Only one y-value can be associated with each x-value.
Thus, A could not represent a function because there are two points with x = 1 and two different y-values: (1, 1) and (1, -2).
B represents a function because for each input (x-value) there is one and only one y-value associated.
C not a function: (2, 3) and (2, -3) have two different y-values associated with one x-value (2).
D not a function: (-3, 4) and (-3, -4) (see A and C, above)
1) Write this as a ratio...
77.5 miles / 3.1 gallons = x miles / 8.2 gallons
Solve for x... multiply by 8.2 gallons on both sides (that cancels it on the right) side of the equation.
8.2 gallons * 77.5 miles / 3.1 gallons = x
635.5/ 3.1 = x
211.83 miles = x
Justin travels 211.83 miles on 8.2 gallons of gas
2) If we let boys = b, then girls has to be b + 15 (since there are 15 more girls than boys). Now together there are 85 members of the band so... boys + girls = 85 and since girls is b + 15, then...
b + b+15 = 85
Now solve for b. First combine like terms...
2b + 15 = 85
Now subtract 15 from each side (cancels the 15 on the left)
2b + 15 - 15 = 85 - 15
2b = 70
Now divide each side by 2 (cancels 2 on the left)
2b / 2 = 70 / 2
b = 35
So there are 35 boys in the band.
Just FYI, that also means there are 35+15 = 50 girls. Just so happens that 50 + 35 = 85 so our work checks!
