Solving systems of equations by substitution

Question

You are trying to decide between two pay-as-you-go cell phone plans. Horizon offers a plan for $30 per month plus $1.30 per gigabyte of data used. BC&C has a plan that costs $10 per month plus $2.50 per gigabyte of data used. What is the “critical point” (amount of data) that will help you to determine the better plan for you? How much will each plan cost at that point?

Answer 1

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