algebra 2 question

anon:

f(x) = -x^2 + -3x +10

The question didn't say but I assume that you are supposed to factorise this?

f(x) = -x ² - 3x +10

i'd start by factorising out -1

f(x) = -1 ( x ² + 3x -10)
f(x) = - ( x ² + 3x -10)

Now you need to find 2 numbers that multiply to give -10 and add to give +3
I can see immediately that one is neg and one is positive (mult to give neg) and the big one is the positive one (they add to a positive)
So straight away i can see it must be +5 and -2

F(x) = -(x+5)(x-2)

Note: whole numbers like 5 and -2 don't always exist.

If i had been thinking properly I would not have done this for you. I would have done a similar question and let you work this one out by yourself.
Arn't you lucky.

If you are keen, why don't you do this question for me.
factorise -2x ² + 8x + 10
Hint: The first thing that you should factorise out is -2