These are the notations that we are going to use
m = Number of training examples
x's = "input" variable /features . (size in feet above)
y's = "output" variable/ target feature (Price above)
(x,y) = single training example
x(i), y(i) = ith training example
lets say we fit this in linear function -> h(x) = Q0 + Q1x
so we are predicting that y is some linear function of x
Above is called linear regression with one variable