SOLUTION: The phone company NextFell has a monthly plan where a customer pays a flat monthly fee, and then a set rate per minute. If a customer uses 380 minutes, the monthly cost will be $19

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Question 1178841: The phone company NextFell has a monthly plan where a customer pays a flat monthly fee, and then a set rate per minute. If a customer uses 380 minutes, the monthly cost will be $196. If the customer uses 690 minutes, the monthly cost will be $335.5.
Find the equation of the plan in the form y=mx+b, where x is the number of monthly minutes used and y is the total monthly cost of the NextFell plan.
y =
If a customer uses 838 minutes, the total cost will be =

Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
Description is same as to find the slope-intercept equation for a line containing the two points, (380, 196) and (690, 335.5).


y=%28%28335.5-196%29%2F%28690-380%29%29x%2Bb

y=0.45x%2Bb
b=y-0.45x
pick either point.
b=196-0.45%2A380
b=25
-
highlight%28y=0.45x%2B25%29