Question

9) f(x) = x +27-1 10x fe Name Sanatha Kuta Software - Infinite Algebra 2 Properties of Parabolas Identify the vertex of each.

Answer 1

Maximum

It is a maximum point when the coefficient of x^2 is negative or when the graph curves downward, we have the maximum value.

`\begin{gathered} \text{Maximum value = }(4ac-b^2)/(4a) \\ a\text{ = -1} \\ b\text{ = 8} \\ c\text{ = -20} \\ \text{Maximum value = }(4*(-1)*(-20)-8^2)/(4*(-1)) \\ =\text{ }\frac{80\text{ -64}}{-4} \\ =\text{ }(16)/(-4) \\ =\text{ -4} \end{gathered}`

Second Method

You can also find the maximum point from the graph at the turning point.

i.e the graph turn at (4,-4)

Hence, the maximum value is the y-coordinate at y = -4