Question 316769
Let x be the amount of medical bills, y be the amount Sam pays. 
A:{{{y=80+0.35(x-80)}}}
B:{{{y=230+0.20(x-230)}}}
To find the crossover point, set the two equal to each other and solve for x.
{{{80+0.35(x-80)=230+0.20(x-230)}}}
Multiply both sides by 100,
{{{8000+35(x-80)=23000+20(x-230)}}}
{{{8000+35x-2800=23000+20x-4600}}}
{{{35x+5200=20x+18400}}}
{{{15x=13200}}}
{{{highlight(x=880)}}}
Once you reach $880 in medical costs, Plan B equals Plan A for Sam. 
Before $880, Plan A is less expensive to Sam.
After $880, Plan B is less expensive to Sam.