Denise's cell phone plan is $29.95 per month plus $.10 per minute for each minute over 300 minutes of call time. Denise's cell phone bill is $99.95. For how many minutes was she billed? Answer is 700 but what is the algebraic equation?

cost = .10(m-300) + 29.95 , where m is the number of minutes

so ....
.10(m-300) + 29.95 = 99.95
.1m - 30 = 70
.1m = 100
m = 100/.1 = 1000

She used 1000 minutes, but is only billed for any time over 300 minutes , look at (m-300) in the equation.
She was billed for 700 minutes

btw, the equation is only valid for m>300
if m<300
it would simply be
cost = 29.95

Let's assume that Denise was billed for "x" minutes of call time.

According to the given information, Denise's cell phone plan costs $29.95 per month plus $0.10 per minute for each minute over 300 minutes of call time. Therefore, the total cost of Denise's cell phone bill can be represented by the equation:
$29.95 + $0.10(x - 300) = $99.95
To find the value of "x," we can solve this equation:
$0.10(x - 300) = $99.95 - $29.95
$0.10(x - 300) = $70
Divide both sides by $0.10:
x - 300 = 700
Add 300 to both sides:
x = 700 + 300
x = 1000
Therefore, Denise was billed for 1000 minutes.

To find the algebraic equation, let's start by defining the variables:

Let "m" represent the number of minutes Denise was billed for.
We know that Denise's cell phone plan is $29.95 per month plus $0.10 per minute for each minute over 300 minutes.

So, for the first 300 minutes, Denise will be billed $0 per minute.
For the remaining minutes (m - 300), she will be billed $0.10 per minute.

Therefore, the equation to calculate Denise's cell phone bill is:
29.95 + 0.10(m - 300) = 99.95

To solve for "m," we will simplify and solve the equation:
29.95 + 0.10m - 30 = 99.95
0.10m - 0.05 = 99.95
0.10m = 100
m = 100 / 0.10
m = 1000

Therefore, Denise was billed for 1000 minutes, not 700.