Acell phone company charges a $10 flat fee plus $0.05 per minute for minutes up to 600. for minutes over 600, the company
charges $0.15 per minute, in addition to the flat fee and the charges for the first 600 minutes.
which function models the company's cell phone charges? !

In both the cases, the given total amount is given as:

T  = 10 + 0.05 m     (when minutes talked m   < 600)

T   =  40   +   0.15 k           (when minutes talked  k   > 600)

Step-by-step explanation:

Here, the flat fee by the phone company = $10

The charge for each minute for  first 600 minutes = $0.05

The per minute cost after 600 minutes  = $0.15

Let us assume the number of minutes talked = m

Case 1: when the minutes talked is less than 600 minutes.

Total Charges = Flat Fee  +  0.05 x ( the minutes talked)

or, T   = $10 + m ($0.05)

or T  = 10 + 0.05 m     (when m  < 600)

Case 2: when the minutes talked is more than 600 minutes.

Let us assume the minutes talked over 600 = k minutes

Total Charges = Flat Fee  + Charges for 600 minutes  +  0.15 x ( the minutes talked over 600)

or, T   = $10 + 600 ($0.05)  + k($0.15)

or T   =  10 + $30     +   0.15 k            (when k   > 600)

⇒  T   =  40   +   0.15 k            (when k   > 600)

Hence, in both the cases, the given total amount is given as:

T  = 10 + 0.05 m     (when m  < 600)

T   =    T   =  40   +   0.15 k            (when k   > 600)

solution:

the given function is ,

      =

the three roots of this quadratic function is , 0 ,8 and 10.all the roots are real and rational.

if a quadratic equation is of the form ,

sum of the roots = a + b +c= 0+8+10=18=  

product of roots taken two at a time = a b + b c+ c a = 0+80+0=80 =  

product of roots = a b c = 0=  

there are 11 doors in a hall starting from 0 to 11.the entry in the hall is permitted through gate number 0 and exit is allowed through only gate number 8 and 10.so, three roots(0,8,10) of quadratic function is given by entry and exit route of this hall.

3x + 4y -25 =0 represents the amount of change sianna should recieve