What is the average rate of change of f(x)=x2+x−6 between x=1 and x=3 ? A
5

B
–5

C
15

D
10

10

Step-by-step explanation:

Substitute 1 in place of x and the result is -4.

Again substitute 3 in place of x and the result is 6.

Change=6-(-4)=10

i assume that by 5 you mean 5 gallons.

(20)(0.25) = 15

removing 15 gallons reduces the tank from 20 to 5.