Hey everyone!

Yesterday I had a math test and got 90% on it. Definitely happy but one question I couldn't solve even tough I knew how to do it...

Let me explain. Please note that English isn't my first language so I might get some words wrong. Also please note that I'm self-learning all math, so the way I solve or write might not be official.

So let's say you need to put the next problem between brackets.

x² +2x -15

I'd solve it like this.

-15 = 1 • -15, -15 • 1, 3 • -5, -5 • 3, -3 • 5 etc

+2x = -3 + 5

Solution x² +2x -15 = (x -3)(x +5)

So I actually know how to solve it. Now my test yesterday threw a curve ball by not having a number before the second x...

It was like this: x² -x -20

I got totally confused because how do I calculate x from -20 like I did in the example I gave? I couldn't because I need to have a number before the x right?

If anyone could explain this to me I'd be very happy!

Thanks!