Question 316076

You are given the slope of a straight line and a point
on that line. Credit remaining is plotted on the y-axis
and total calling time is on the x-axis
{{{m = -.15}}}
(x,y) = (27,34.05) 
the formula to use is:
{{{m = (y - y[1])/(x - x[1])}}}
{{{-.15 = (y - 34.05)/(x - 27)}}}
{{{-.15*(x - 27) = y - 34.05}}}
{{{-.15x + 4.05 = y - 34.05}}}
{{{y = -.15x + 38.1}}}
Now solve for y, given the point (34,y)
{{{y = -.15*34 + 38.1}}}
{{{y = -5.1 + 38.1}}}
{{{y = 33}}}
There is $33 credit after 34 min of calls