Two cell phone companies have different rate plans. Runfast has monthly charges $25 plus $10 per gig of data. B A &D’s monthly charge is $18 plus 15 per gig of data. Your task is to determine under what circumstances each company has the better pricing.

Okay I am trying to do the substitution method for this problem. I found their monthly prices and put them in an equation like it asked.

25+10x-RunFast

18+15x-BA&D

I need help with solving these equations using the substitution method. I got 132-150x for 25+10x, but I am pretty sure that is over the top incorrect. I have no idea how to do this, and help would be really appreciated.

let the number of gigs used be g

Runfast:
cost = 25 + 10g

BA&D:
cost = 18+15g

let's see for how many g's the plans are the same
cost of one = cost of the other
18+15g = 25+10g
5g = 7
g = 7/5 = 1.4 gigs

so for 0 gigs over, BA&D would cost $18 vs $25 for Runfast, so

BA&D is the better plan if you stay below 1.4 gigs
and Runfast is better if your use more than 1.4 gigs

thanks:) I totally needed the help!

To determine under what circumstances each company has the better pricing, we need to solve the given equations using the substitution method correctly. Let's start from the beginning.

The monthly cost for Runfast is $25 plus $10 for each gig of data, which can be represented by the equation:

Cost(Runfast) = $25 + $10x

Where x represents the number of gigabytes of data used.

Similarly, the monthly cost for B A & D is $18 plus $15 per gig of data:

Cost(B A & D) = $18 + $15x

To determine under what circumstances each company has the better pricing, we need to compare the costs for different values of x.

Now, let's solve these equations using the substitution method:

Step 1: Set the two equations equal to each other:
$25 + $10x = $18 + $15x

Step 2: Simplify the equation:
$10x - $15x = $18 - $25
-$5x = -$7

Step 3: Divide both sides of the equation by -5 to solve for x:
x = -$7 / -$5
x = 7/5 or 1.4

Now that we have found the value of x, we can determine under what circumstances each company has the better pricing. We'll substitute this value back into the original equations:

For Runfast, with x = 1.4:
Cost(Runfast) = $25 + $10(1.4)
Cost(Runfast) = $25 + $14
Cost(Runfast) = $39

For B A & D, with x = 1.4:
Cost(B A & D) = $18 + $15(1.4)
Cost(B A & D) = $18 + $21
Cost(B A & D) = $39

Both companies have the same pricing when x = 1.4, which means that if you plan to use 1.4 gigabytes of data, both companies will charge you the same amount of money.

To determine which company has the better pricing under different circumstances, you can compare the costs at different values of x. If x is less than 1.4, Runfast will have the better pricing. If x is greater than 1.4, B A & D will have the better pricing.