The equation has to be put into a Y=mx+b format. Basically warp this equation to fit your needs. Make the Y (y intercept) equal S. m (slope) equal $14. x (x coordinate value) equal months or m. Then the b equal $458.
So essentially it will be S=$14m+$458.
It’s this because S is the total value you’re trying to get (the savings)
$14 is linear meaning it’s the same every time or in this case every month so it goes there since the amount also depends on the amount of months. Which is also why m (months) is being multiplied by $14. $458 goes there because it’s the starting value so it will be accounted for every time you calculate with this equation.
I apologize if anything is incorrect or unclear and if you have any questions please ask.