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Help with a general maths question, please

Hi all,

I came across this question:

When a+b = 3 and c+w = 4, what does ac+bw+aw+bc = ?


I don't really know how to even start this question, could someone help me out please?



Thanks!

Scroll to see replies

Reply 1
why dont you multiply them together what does that get you (a+b)(c+w)=3*4 feel free to ask if you need more help
Reply 2
do you notice what the two factors make
Original post by londoncricket
Hi all,

I came across this question:

When a+b = 3 and c+w = 4, what does ac+bw+aw+bc = ?


I don't really know how to even start this question, could someone help me out please?



Thanks!


Factorise everything

Hint:

ab+bc=b(a+c)ab+bc = b(a+c)
(edited 9 years ago)
Reply 4
Original post by Indeterminate
Factorise everything

Hint:

ab+bc=c(a+b)ab+bc = c(a+b)

This is a red herring and quite useless.
Reply 5
Original post by Old_Simon
This is a red herring and quite useless.


No its not

Factorise as follows:

ac+bw+aw+bc
=ac+aw+bc+bw
=a(c+w)+b(c+w)
=(a+b)(c+w)

I trust op can finish it from here and i imagine seeing that you shoukd factorise like so caused you problems. If it helps, icould tell you needed to factorise and end up withsomething like what you did because there were 4 terms so this is the expansion of two brackets each with two terms and each term contained only 2 variables
Reply 6
Original post by newblood
No its not

Factorise as follows:

ac+bw+aw+bc
=ac+aw+bc+bw
=a(c+w)+b(c+w)
=(a+b)(c+w)

I trust op can finish it from here and i imagine seeing that you shoukd factorise like so caused you problems. If it helps, icould tell you needed to factorise and end up withsomething like what you did because there were 4 terms so this is the expansion of two brackets each with two terms and each term contained only 2 variables


This q has nothing to do with factorising. It requires an expansion.
Reply 7
No it required factorising


Guessing that the product would give you the expression is expansion. While that is perfectly appropriate and sensible if you cant see how to factorise in this situation, the"proper" or perhaps intended method is to factorise
Reply 8
Both methods work!
Reply 9
Original post by Old_Simon
This q has nothing to do with factorising. It requires an expansion.


I disagree


Original post by newblood
No it required factorising


Guessing that the product would give you the expression is expansion. While that is perfectly appropriate and sensible if you cant see how to factorise in this situation, the"proper" or perhaps intended method is to factorise


Well said
Original post by TenOfThem
I disagree




Well said

It depends on which end of the problem we start. The exapansion obviously equals the factoring.
Original post by Dualcore
Both methods work!

this
Any way the answer is obviously 12 whatever.
Original post by Old_Simon
It depends on which end of the problem we start. The exapansion obviously equals the factoring.


exactly
Original post by TenOfThem
exactly

:smile:
Reply 15
Were you looking for the answer, as one person has gone for,
or did you want the formula, as most went for ?

How to start...
A clue to you, all your letters are the symbolic representation of a number, !
It,s only maths, called algebra, that,s the fun, working it all out....
The answer is, Narrr i.ll spoil it....
Wow! Thanks to everybody that replied much appreciated I am very surprised that I didn't manage to see that it was a relatively simple factorising question?!

Thanks again!
Reply 17
Original post by londoncricket
Wow! Thanks to everybody that replied much appreciated I am very surprised that I didn't manage to see that it was a relatively simple factorising question?!

Thanks again!


Curiosity asks, What was your answer ?
Original post by yellsah2
Curiosity asks, What was your answer ?



I didn't really have one, actually.
Reply 19
Original post by londoncricket
I didn't really have one, actually.



Good to see someone having a bit of fun with something that stretches the mind ,
a lot of gobbledygook answers, and they were fun....to look at...

But one person said, Answer is 12 , correct ...

But how do we get 12 is the real knowledge,

ie, someone my have the right theory, and get the wrong answer,
no problem, as its the theory first, then maths.

Wanna know how 12 ? Have a good Sunday.

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