Question

How do u find the range of a graph? A quadratic one?

Answer 1

example
find range of f(x) = x^2 - 5x + 4
the graph will look like a U so will have a minimum value
you can plot the graph to find the range or you can convert the function to vertex form
by completing the square

x^2 - 5x + 4 = (x - 2.5)^2 - 2.5^2 + 4
- the x coordinate of the vertex is 2.5
and y = (2.5)^2 - 5(2.5) + 4 = 6.25 - 12.5 + 4 = -2.25
this is minimum value of f(x)

so the range is [-2.25, infinity)

functions having a negative x^2 have upside down U shape so have a maximum value

Answer 2

OMG, thx so much!!