1. ## VERY simple question about solving equations

Hello.

This question may seem a little unusual but I'm desperate about it.

So I have this equation:

y = (x^2 + 3x) - (2x + 3)(x - 1)

my question is: do I have to first apply the minus sign, or do the parenthesis first? I'm really confused about it and I feel ashamed (really! )

Can you please show me how to solve this? Thank you

2. ## Re: VERY simple question about solving equations

I guess you have to solve:
$\displaystyle 0=(x^2+3x)-(2x+3)\cdot (x-1)$
The multiplication precede the subtraction.
First expand $\displaystyle (2x+3)\cdot (x-1)$.
So you'll have something like:
$\displaystyle 0=(x^2+3x)-(...x^2+...x+...)$
The brackets are important!

3. ## Re: VERY simple question about solving equations

Please Excuse My Dear Aunt Sally!

Calculations inside (P)arentheses are done first, then (E)xponents, then (M)ultiplication and (D)ivision, and lastly (A)ddition and (S)ally.

4. ## Re: VERY simple question about solving equations

In that case we would have :

y = (x^2 + 3x) - (2x + 3)(x - 1)

y = (x^2 + 3x) - (2x^2 + x - 3)

Now I apply the minus in :

y = (x^2 + 3x - 2x^2 - x + 3) ==> -x^2 + 2x + 3

right? I don't think so

5. ## Re: VERY simple question about solving equations

Yes, that's right!