Question

factor completely -4x^2+16x-24

Answer 1

I think the answer is -4(x^2-4x+6)

Answer 2

@phi

Answer 3

(-b+√(4ac))/2a

(-b-√(4ac))/2a

Answer 4

what???

Answer 5

plug the numbers in for a, b, c

Answer 6

wait so is my answer correct???

Answer 7

if you didn't learn about the Quadratic Equation then it's correct.

Answer 8

okay I didn't sooo I guess Im good. what about this one factor completely -5x^3+10x^2

Answer 9

-5x^2(x-2)

Answer 10

thanks sooo much :)

Answer 11

This is not a "solve" problem, there is no equation as there is no equal sign. It is an expression that is to be factored completely (in to prime factors)
You have started the problem correctly:
-4x^2+16x-24
-4(x^2-4x +6) This is as far as it can be factored. The quadratic formula is for solving quadratic "equations" not for factoring expressions.

Answer 12

@radar there are apparently some teachers who suggest that you use the quadratic formula to find the roots and then turn them into the factors...

Answer 13

@whpalmer4 Sorry I wasn't aware of that, learn more every time I log on here, thanks for the use of the quadratic formula applied as a factoring method.

Answer 14

it's crazy, if you ask me, but I see it suggested by so many people that someone must think it is a good idea. I suppose it is easier to tell someone "here, just put your numbers in here" than to explain factoring.