The Student Room Group

I don't understand this question...

FORMING AND SOLVING EQUATIONS!X

Mavis has three bags containing n marbles each and six loose marbles.
Circle the formulas below that show how many marbles,m,Mavis has.

The formulas:

M=6n
M=n+6
M=3n+6
M=3(n+2)
M=3(n+6)

I don't want you to give me the answer straight away,but I would like you to explain it first if you give me the answer. So please talk me through it!x
Reply 1
3 bags = 3n
+6 for the six marbles, so
M=3n+6

and
M=3(n+2)
because if you expand the bracket (multiply everything in it by 3) you also get M = 3n+6
Original post by nox1
3 bags = 3n
+6 for the six marbles, so
M=3n+6

and
M=3(n+2)
because if you expand the bracket (multiply everything in it by 3) you also get M = 3n+6


Thanks,so shall I cirlce all three or just the two? Where does the +2 come from?
(edited 9 years ago)
Reply 3
Original post by Student-Dancer
Thanks,so shall I cirlce all three or just the two? Also,I don't understand what the M is...:smile:


Just circle M = 3n +6 and M = 3(n+2)

M is a letter that represents 'number of marbles'

:smile:
Original post by nox1
Just circle M = 3n +6 and M = 3(n+2)

M is a letter that represents 'number of marbles'

:smile:


Where does the +2 come from?
3n+6 because she has 3 bags of n + 6 loose marbles so 3 x n + 6 or 3n+6

3(n+2) is a simplified version of this so it's also right
(edited 9 years ago)
Reply 6
Original post by Student-Dancer
Where does the +2 come from?


If you have the M = 3n + 6, the +2 comes from factorizing it (putting it into brackets).
M = 3 x (n + 2), because 6/3 is 2, leaving the + 2.
Another way of thinking about it is, in order to factorize it, everything inside the brackets has to be divided by the number outside the brackets, and when expanding the brackets, everything inside the brackets has to be multiplied by the number outside the brackets (in this case, 3).

I'm sorry if this doesn't make sense, it's kind of hard to explain over typing :colondollar:
So basically I have to factorize it by taking the 6 and dividing it by 3? What do you mean by expanding,sorry I have never learnt this.
Original post by Student-Dancer
So basically I have to factorize it by taking the 6 and dividing it by 3? What do you mean by expanding,sorry I have never learnt this.


Original post by nox1
If you have the M = 3n + 6, the +2 comes from factorizing it (putting it into brackets).
M = 3 x (n + 2), because 6/3 is 2, leaving the + 2.
Another way of thinking about it is, in order to factorize it, everything inside the brackets has to be divided by the number outside the brackets, and when expanding the brackets, everything inside the brackets has to be multiplied by the number outside the brackets (in this case, 3).

I'm sorry if this doesn't make sense, it's kind of hard to explain over typing :colondollar:

So basically I have to factorize it and divide 6 by 3? What do you mean by expanding brackets...How would I do this? Sorry,I haven't learnt this yet:smile:
Reply 9
Original post by Student-Dancer
So basically I have to factorize it and divide 6 by 3? What do you mean by expanding brackets...How would I do this? Sorry,I haven't learnt this yet:smile:


yep! expanding brackets is taking away the brackets. It's fine :smile:
e.g. 3(4 + 2x), expanded would be 12 + 6x, because you multiply everything in the brackets by the number outside the brackets
Original post by nox1
yep! expanding brackets is taking away the brackets. It's fine :smile:
e.g. 3(4 + 2x), expanded would be 12 + 6x, because you multiply everything in the brackets by the number outside the brackets


Thank you ever so much:smile:))

Quick Reply

Latest