Answer :
y = mx+b is slope-intercept form
m = slope = 3
b = y intercept = 5
The 'm' can be thought of how to move while the 'b' could be thought of where to begin.
We begin at 5 on the y axis which is the location (0,5). Then move up 3, right 1 to arrive at (1,8). Recall that m = slope = rise/run.
Together the slope and y intercept help us determine which two points to plot so we can draw a straight line.
-------------------------
A real world application
You start with $5 in savings which is the y intercept or where you begin (ie it's the value of b). Each day you earn $3 which is the slope value telling us how much the amount of money increases or moves (it's the m = 3 discussed earlier)
x = number of days
y = account balance
The 3x is how much extra dollars you add onto the starting $5
Therefore 3x+5 is the total amount of money you'll have after x days.
If you wanted to know how much money you'd have after say x = 10 days, then you'll have y = 3x+5 = 3*10+5 = 30+5 = 35 dollars would be the account balance.
