Factor completely:
n^2-9n+8
Please help.

Question

Factor completely:
n^2-9n+8
Please help.

unklerhaukus · Answer

what are some factors of 8, that add to -9?

unklerhaukus · Answer

(the factors can be positive or negative)

anonymous · Answer

-8 and -1 ?

unklerhaukus · Answer

good

anonymous · Answer

(n-8)(n-1)
n=8 or n=1 
am I right ? 
@UnkleRhaukus

unklerhaukus · Answer

your first line is all this question is asking for

if it was   n^2-9n+8=0   then   your would be right that x=8 or 1
but there was no equal sign in the original expression

anonymous · Answer

I know, but the whole point of this question is I think to find what n could be..

unklerhaukus · Answer

if you want to check it
just expand the brackets, you should get the expression in the question

(n-8)(n-1)=(n×n)+(n×-1)+(-8×n)+(-8×-1)

unklerhaukus · Answer

oh i thought you just had to Factor completely

anonymous · Answer

oh... I see. thank you;D

unklerhaukus · Answer

but if this was just a sub question to a larger problem , then your probably right

anonymous · Answer

ohh.... could you help my with this one too:
7x^2-45-28
what should I do with the 7?
@UnkleRhaukus

unklerhaukus · Answer

this one isn't so simple

i would set it equal to zero , and apply the quadratic formula

$$ax^2+bx+c=0$$
$$x_{1,2}=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$$

$$ax^2+bx+c=(x-x_1)(x-x_2)$$

anonymous · Answer

but they want me to factor it Completely...

unklerhaukus · Answer

(x−x_1)(x−x_2) is the factored form

unklerhaukus · Answer

7x^2-45-28=0

what is a,b,c?