Answer:
8.60 units (3 s.f.)
Step-by-step explanation:
The distance between 2 points is given by the formula:

Thus using the above formula,
Distance between (-10, 9) and (-5, 2)

Do you have a picture? i can help if you have one
To answer this, first make an equation representing the data:
15+ 0.20X= Bill
now plug in data you know:
15 + 0.20(30)= bill
and finally solve it:
Bill= $21.00
10 divided by 2 is 5, 5 + 8 is 13
thus f(10)= 13
hope this helps