Maths Homework Help

[MrTiddlesTheCat]

Does anyone know the answer to this maths question? My brain is starting to leak out of my ears.

Factorise
(a+3)2-(b-3)2

The 2s are both supposed to be 'squared' but my computer finds it amusing to sod about with exponents.

Can you do (a+3)^2

I did. Then it changed to just '2' when I clicked on 'post'.

What I mean is - can you calculate that answer?

Multiply out the brackets first (carefully):

a squared +9 +6a - (b squared +9 +6b)

Simplify:

a squared -b squared + 6a-6b

= (a-b)(a+b) +6 (a-b)

= (a+b+6)(a-b).

Hopefully, I haven’t made any careless errors…

(a+b)(a-b+6)

Trying again on a different computer.

(a+3)²-(b-3)²

That's just giving the answer away!

@cakeorwine ,

I thought that was the point! But I also explained it…

I am assuming it is a parent asking to help their child and not some pupil asking!

It's a difference of 2 squares question...

But is it the correct answer?

@Newbutoldfather -(--6b) rather than -(+6b)?

@Overtheatlantic ,

You can always check the answer by multiplying out. That is the beauty of maths.

@LikeABat ,

I think you are right, sorry. Why I always tell my children that maths is so much better on paper than screens!

Without going over it again:

(a-b+6)(a+b)

I agree with the above...

Computer says no.

Yes! Genius. My scientist husband has come up with 3 solutions, all of which were 'no's.

Thank you.

I corrected it and another poster also attached a nicely worked solution (on paper!) that agreed with my correction.

So have you or your DC tried to do the steps here:

1. Do each bracket - multiply them out
2. Subtract the second answer from the first

Then rearrange - what level is this aimed at?

So does the person who needs to do it understand how to multiply out brackets?

It's me that's doing it. But I don't really need to understand the maths as such, so I'm not really cheating. I will go through the workings out to figure it out though as I want to understand.

I'm in Sweden and here there are schools for adults who didn't get their leaving certificates. Just like kids schools we have a timetable of various lessons and we have to attend all. I'm there just to learn Swedish as I completed school in the UK so don't need a grade in maths.

Thank you everyone for your help.

Sometimes I do and sometimes I don't. I had no problem doing it in school 40 years ago. The brain doesn't fire on all cylinders these days.

(a+b)^2 = (a+b)(a+b)

So you need to know how to expand those brackets - various methods are available.

The grid method is good as it clearly shows the multiplication steps