Question

Let f(x) be a quadratic function. If the coordinates of the vertex of the graph of y=f(x) are (3,-4), which of the following must be true?
A. The roots of the equation f(x)=0 are integers.
B. The roots of the equation f(x)-3=0 are rational numbers.
C. The roots of the equation f(x)+4=0 are real numbers.
D. The roots of the equation f(x)+5=0 are non real number.

Answer 1

know the vertex co-ordinates ?

Answer 2

just need to find what b^2-4ac is

Answer 3

do I need to find the formula?

Answer 4

an expression for the quadratic function may help.

Answer 5

I go for a dinner first, see you later, thank you.

Answer 6

since the vertex of the quadratic function is given, we can write the function as \[\huge f(x)=a(x-3)^2-4\] for any non-zero a.

Answer 7

and then?