Fill in the missing term so that the quadratic equation has a graph that opens up, with a vertex of (– 2, – 16), and x intercepts at x = -6 and x = 2. (Do not include the negative sign in your answer.) y = x2 + 4x − ___

Question

Fill in the missing term so that the quadratic equation has a graph that opens up, with a vertex of  (– 2, – 16), and x intercepts at x = -6 and x = 2. (Do not include the negative sign in your answer.)   y = x2 + 4x − ___

saifoo.khan · Answer

Since you know the x-intercepts.. You can find the whole equation..

saifoo.khan · Answer

x = -6 and x = 2

(x+6) = 0     and    (x-2) =0

Now combine,

(x+6)(x-2) = 0

Try using FOIL now..

anonymous · Answer

i am just not very good at working backwards

anonymous · Answer

what the heck is FOIL

saifoo.khan · Answer

Aluminium foil..

saifoo.khan · Answer

This is foil: http://costaricasailing.net/sportfishing-costarica.com/wp-admin/maint/algebra-foil-method-examples-715.jpeg

anonymous · Answer

ok i know about that i just hadn't heard the acronym before :)

saifoo.khan · Answer

Ah. Okay.
The term is widely used in US though.

anonymous · Answer

i'm in the US and i still haven't heard of it :)

saifoo.khan · Answer

I see..