y = mx + b

y = how far up

x = how far along

m = Slope or Gradient (how steep the line is)

b = value of y when x=0

How do you find "m" and "b"?

• b is easy: just see where the line crosses the Y axis.

• m (the Slope) needs some calculation:

y = 2×1 + 1 = 3

Check for yourself that x=1 and y=3 is actually on the line.

Or we could choose another value for x, such as 7:

y = 2×7 + 1 = 15

And so when x=7 you will have y=15