Answer:
3rd one
4th one
5th one
8th one
Step-by-step explanation:
solve for the y intercept by plugging in f(0)
0²-4(0)-21= -21
Therefore (0,-21) is a y intercept
Factor to find the x intercepts
(x+3)(x-7)
Therefore the intercepts are
(-3,0) (7,0)
THis function has a positive coeficcent and an even degree
therefore as x approaches infinity it's infinity
and as x approaches negative infinity it's infinity