Phone plan A charges $1.25 for the first minute and $0.15 for every minute thereafter. Phone plan B charges a $0.90 connection fee and $0.20 per minute. Which of the following equations could be used to find the length, in minutes, of a phone call that costs the same under either plan?

(A) 1.25 + 0.15x = 0.90x + 0.20
(B) 1.25 + 0.15x = 0.90 + 0.20x
(C) 1.25 + 0.15(x – 1) = 0.90 + 0.20x
(D) 1.25 + 0.15(x – 1) = 0.90 + 0.20(x – 1)
(E) 1.25 + 0.15x + 0.90x + 0.20 = x

The answer is (C) .

Step-by-step explanation:

Now, to find the equation for finding the length, in minutes, of a phone call that costs the same under either plan.

Let the phone charges per minute be

So, to get the equation of the phone plan A as the phone plan A charges $1.25 for the first minute and after that $0.15 for every minute:

Now, to get the equation of the phone plan B as given phone plan B charges a $0.90 connection fee and $0.20 per minute:

As, the phone call that costs the same under either plan.

Thus:

Therefore, the answer is (C) .

The equation is:

y = (-8/11)X + 1

Step-by-step explanation:

y = M x + b

(33, -23) means x=33 and y=-23 with M = -8/11

-23 = (-8/11)(33) + b

-23 = -24 + b <  11 cancels 33 by a factor of 3, which multiples by -8 to give -24

-23 + 24  = -24 + b + 24 <--- adds 24 to both sides

1 = b