Question

Practice using the quadratic formula.

Answer 1

I'll do f(x) as an example.
\(f(x)=x^2+6x+8\)............(1)
f(x) has real roots if \(b^2-4ac\ge 0\), where
\(f(x)=ax^2+bx+c\)..........(2)
By comparison of (1) and (2), we conclude that
a=1
b=6
c=8
and
\(b^2-4ac=6^2-4*1*8=36-32=4\ge 0\)
therefore f(x) has real roots (i.e. check box filled for f(x)).
I'll let you figure out the rest, and post your answers if you wish.