Question 732985
Plan A cost $20 per month plus $0.15 for each minute used. Plan B cost $15 per month plus $0.20 for each minute used. What equation can be written to represent the cost of each plan? After how many minutes is the cost the same? 
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A(x) = 20 + 0.15x
B(x) = 15 + 0.20x
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Graphing:
y = 20 + 0.15x
Let x = 0, then y = 20
Let x = 100, then y = 20+15 = 35
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Plot the 2 points and draw a line thru them.
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y = 15 + 0.20x
Let x = 0, then y = 15
Let x = 100, then y = 15+20 = 35
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Plot the 2 points and draw a line thru them.
{{{graph(400,400,-25,150,-25,75,20+0.15x,15+0.20x)}}}
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Equation:
20 + 0.15x = 15+0.20x
5 = 0.05x
x = 100 minutes
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Cheers,
Stan H.
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