Question

Parabolas and their intercepts.. Please help? Question attached.

Answer 1

do you know what the quadratic formula is? does it sound familiar to you?

Answer 2

No, I am trying to check my sisters answers and this lesson does not have a key.

Answer 3

hmm... it looks like this could be done with factoring instead.
\[4x^2-4x-8 \Rightarrow 4(x^2-x-2) \Rightarrow 4(x+1)(x-2) = 0\]

Answer 4

Before you do the quadratic formula you should divide all the terms by 2 (common in all numbers- 4, 4 and 8).
So you'll have 2x^2 - 2x - 4
Then you see you can divide it by 2 again, so you have: x^2 - x - 2

Then use the quadratic formula - -b+/- (square root)b^2-4ac divided by 2a