Tyrell plans to run each week for 4 weeks - write a function equation from table

x/y
1/5
2/9
3/13
4/17

2 answers

note that when x increases by 1, y increases by 4.
That means the slope of the line is 4, so the place to start is

y = 4x

That doesn't quite fit, so adjust it to bring it into line.
notice that for every increase of 1 in the x, the y increases by 4
so it must be y = 4x + ??
normally I would write this as y = 4x + b
now sub in one of the points, say (1,5)
5 = 4(1) + b
b = 1

y = 4x + 1

check to make sure the other points work in this equation