Josephs lunch at a restaurant $13.00 , without tax he leaves the waiter a tip of 17% of the cost of the lunch without tax what is the total cost of the lunch including the tip without tax

The answer would $15.21.

Tip would be 17% of $13.00:

In order to find that you would do

13.00 x .17 = 2.21

13.00+2.21 = 15.21

Since x can be any real number the domain is (-infinity,infinity)

 

To find the range we need to find the vertex of the parabola which is at (-b/2a , y)

-b/2a would be 2/2 = 1 ... so find the y value at x = 1

12 - 2(1) - 15 = 1-17 = -16

So the vertex is at (1,-16)

Since the parabola opens upward from that point the minimum value of the range is y = -16

The range would include the point -16 so it is actually

R = [-16,infinity)