1. ## Factoring, completeing square.

Hello and thank you all for the help.

I am working on a problem and I am completely at a loss.

this is the problem I am working on.

(x-10)(x-2)=-20

now I think this is what I am supposed to do,

x^2-12x+20=-20
+20 +20
x^2-12x+40=0

this is were I am lost.

2. Hello,

What is the exact question ?

The equation you got has no real solution ;-)

I think they want you to complete the equation to got a perfect square.
So use (a-b)²=a²-2ab+b², with a=x and 2ab=-12

3. Sorry,
The chapter we are in is Quadratic formula, Factoring and completing the square. and the question is Solve the each equation by the method of your choice.

I can't however find an example of an equation of this type in the entire chapter. So I am pretty lost.

4. I'll give that a try.

5. Ow !

If you try to make a square :

x²-12x + ??? = ??

With ??? a perfect square that will let you factorize x²-12x+??? to a square

So a=x
2ab=12x, with b²=???

So b=6.

So you must make appear 36 in the term.

Which will give :

x²-12x+20=20 <=> x²-12x+36=4 <=> (x-6)²=4=2²

6. Great, I was so close but I just wasn't confident in what I was doing.

Thanks so much for the help.

7. Originally Posted by EricS
Hello and thank you all for the help.

I am working on a problem and I am completely at a loss.

this is the problem I am working on.

(x-10)(x-2)=-20

now I think this is what I am supposed to do,

x^2-12x+20=-20
+20 +20
x^2-12x+40=0

this is were I am lost.
Let a polynomial be $Ax^2 + Bx + C = 0$

You have to use the quadratic equation: $x = \frac{-B \pm \sqrt{B^2 - 4AC}}{2A}$

8. i hope you better use the distributive propety and then find its value.........