There are infinitely many lines that have the point (1,-3).
A line can be expressed as:
y=mx+b, where m=slope and b=y-intercept..
Our only restriction is that it passes through (1,-3) so
-3=1m+b
So as long as the sum of the slope and the y-intercept is equal to -3, that is one of the infinite number of lines that passes through (1, -3)
So we could also say b=-3-m then our infinite lines are:
y=mx-3-m, now any real value of m creates a specific line that passes through the point. ie the first few are
y=x-4, y=2x-5, y=3x-6 or even y=x√2-3-√2
155/(2 1/2)=62
Sam drives at 62 m/h
62*4=248
Sam would drive 248 miles in 4 hours.
Hope this helps :)
When solving for a coefficient the variable to look for is 1
