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# If x is positive, why take the negative root?

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1. (Original post by frostyy)
Thanks! I understand now. I appreciate the help.
2. (Original post by frostyy)
Thank you! Just to be clear on this though, I thought that if I have x outside the brackets on one side of the equation, I should divide everything on the other side by it to take it out?

So x(4-x) = x^2(7-x)
4 - x = (x^2 / x)((7 - x) / x)

I understand that I'm wrong now though.
No. Don't divide by .

You have . Move it all over to one side. You pick which. I'll go with .

This then gets by factoring an out. Simplifying and expanding the brackets inside gets you as required by the question in part (ii).

Also, when even though you're dividing by x (which isn't correct) you're doing it incorrectly.

Do you think that means that if you divide by sides by 10 you get ?

That would get you . And you know that 1 isn't 0.1?

Instead, if you divide by 10, you divide the entire RHS by 10 only once. So .

Analogously: When you have if you were to divide by (which you shouldn't do!) but if you did for the bantz, you should get:

and NOT

Hope that clears up some stuff.

tl;dr

1. then dividing by gets you .

2. then dividing by gets you .

Edit: sorry if this comes across as a bit blunt, it's 2:30 a.m and I want to make sure that you nip all these misconceptions before they become bad habits.
3. (Original post by Zacken)
No. Don't divide by .

You have . Move it all over to one side. You pick which. I'll go with .

This then gets by factoring an out. Simplifying and expanding the brackets inside gets you as required by the question in part (ii).

Also, when even though you're dividing by x (which isn't correct) you're doing it incorrectly.

Do you think that means that if you divide by sides by 10 you get ?

That would get you . And you know that 1 isn't 0.1?

Instead, if you divide by 10, you divide the entire RHS by 10 only once. So .

Analogously: When you have if you were to divide by (which you shouldn't do!) but if you did for the bantz, you should get:

and NOT

Hope that clears up some stuff.

tl;dr

1. then dividing by gets you .

2. then dividing by gets you .
That is a long ass explanation and I'm surprised that you're bothered, but nevermind, I owe you a beer or something. Hit me up when you're in the South West
4. (Original post by frostyy)
That is a long ass explanation and I'm surprised that you're bothered, but nevermind, I owe you a beer or something. Hit me up when you're in the South West
Haha, I figured it'd be best if I nip your misconceptions before they become bad habits. That happened to me when I was younger... never again.

If it's too long, don't bother now, but make sure you go over it with a fine tooth comb tomorrow morning and understand precisely what's going on, it'll be worth your while.

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