Thread: check my work on quadratic equations?

can someone check this for me?

what about this one?

No, both are wrong (first one in the answer, second one in the writing)

In the first one, you must write both answers :

and

The second one has the correct answer but is not correctly written. Here is an example of how it should be written :









or

or

Thus



EDIT : talking about the first question in this post ...

You must show all your working

What if I didn't know what the quadratic formula was?

You're up to here:



The next bit is wrong. You didn't factor 2 out of the -4.

The other question you posted is wrong too
I am not taking account of the quadratic equation written on it because I do not see the link with the following.

Here is how you do it :



--> This is where you messed up : you did not factorize the .



Or, more conveniently :

can someone help me understand the factorization part?

Remember that . Here, you have :



This can be written :



The common factor is two, so you factorize it over the addition. Since you are factorizing all the (and not !), they become (some people prefer to remove them directly though) :



Now you can cancel out :



Which is simplified to :



Or, even more conveniently :

still dont really folllow, sry

alright let's break it down.

We have



if we had

we would factorise it by taking 2x out of the equation.

So we divide all terms by 2x:



So same as

we can take 2 out of the equation;

So divide everything by 2
you will get:

I divided the -4 by 2 (which made -2) and 2 by 2 ( which made 1)

Is this more clear now?

i think i got it now, thx a bunch

Cool!