A pay phone at a shopping mall charges $0.68 for the first four minutes and $0.21 for each extra minute (or part of a minute). Find the cost of a 13.44-minute call on this phone

2.78 dollars

step-by-step explanation:

hello there!

first we multiply 10 to $ 0.21 ( we got the number 10 from the extra 10 minutes after the first 4 minutes )

10 + $ 0.21

= 2.10 dollars

then we need to add $ 0.68 to $ 2.10 dollars

$ 0.68 + $ 2.10

= 2.78 dollars

2.78 dollars is how much it costs for a 13.44 minute call!

i hope this helps you and please tell if there was a mistake in this, have a wonderful day! <3

if the eqn of the parabola is f(x) = (x-4)(x+2), we need to mult. this out to find the coordinates of the vertex.

then f(x) = x^2 + 2x - 4x - 8, and f(x) = x^2 - 2x - 8.

one way in which you can find the vertex is to calculate x = -b / (2a).   here, that comes to

        )

x = = 1.   f(1) = 1^2 - 2(1) - 8 = - 9.   vertex is at (1, -9).

        2(1) 

find another point on the curve:   let x=0, for which y=-8.   then (0, -8) is on the curve.   plot the vertex and this point and draw a smooth parabola thru both.

hope this

i dont know

step-by-step explanation: