He subtracted the 29fron the 30
If the parent graph f(x) = x² is changed to f(x) = 2x², the vertex of the parabola will still remain (0, 0) because whenever the equation of a parabola is in the form y = ax², the vertex will always be (0, 0).
Now if <em>a</em> is a big number, the parabola will become narrower.
So it will stretch vertically and become narrower.
Range= 4
Range is the highest number minus the lowest number, 10-6=4
