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Maths question?

Hi, can someone check my working out for this question and tell me if what I’ve done makes sense/point out where I’ve gone wrong.

(Bottom pic only, accidentally added 2 but woo you get to see my friend’s grades)
(edited 7 months ago)
Reply 1
Looks ok, but assuming youre getting assessed on line, the usual form would be to put the y^(-11) on the denom as y^11. Similarly, doing that at the start/throughout the working would be more usual.

Edit - note a simpler/quicker way to do it would simply to consider the x, y and z terms independently and then multiply at the end. So the y's would give
1/y^2 * 1/y^9 = 1/y^11
...
(edited 7 months ago)
Reply 2
Original post by mqb2766
Looks ok, but assuming youre getting assessed on line, the usual form would be to put the y^(-11) on the denom as y^11. Similarly, doing that at the start/throughout the working would be more usual.

Edit - note a simpler/quicker way to do it would simply to consider the x, y and z terms independently and then multiply at the end. So the y's would give
1/y^2 * 1/y^9 = 1/y^11
...


Right, got it thank you!

I put it into that form you said is preferable to get x^3/y^11 z^2

But the answer is x^3/ y^11 z

So no z^2. Can you see anything I may have done wrong?
Reply 3
Original post by subbhy
Right, got it thank you!

I put it into that form you said is preferable to get x^3/y^11 z^2

But the answer is x^3/ y^11 z

So no z^2. Can you see anything I may have done wrong?


Where is the z^2? I can't see it.
Reply 4
Original post by Muttley79
Where is the z^2? I can't see it.


Ah here unless I’ve made an error when simplifying? 9225259B-45F9-4E89-9F64-4F07634BAC19.jpg.jpeg
Reply 5
Original post by subbhy
Ah here unless I’ve made an error when simplifying? 9225259B-45F9-4E89-9F64-4F07634BAC19.jpg.jpeg


This isn't the same as your second attachment - can you post the whole question in one picture?
Reply 6
Original post by subbhy
Ah here unless I’ve made an error when simplifying? 9225259B-45F9-4E89-9F64-4F07634BAC19.jpg.jpeg


In the OP you had just z on the denominator which is correct.
Reply 7
Original post by mqb2766
In the OP you had just z on the denominator which is correct.


I thought to put it into the more desirable format I had to do this stuff I did at the end?
Reply 8
Original post by Muttley79
This isn't the same as your second attachment - can you post the whole question in one picture?


Apologies here it is
52C94831-BC7C-4C95-BCD2-7EF2B7AC8B04.jpg.jpeg
Reply 9
Original post by subbhy
I thought to put it into the more desirable format I had to do this stuff I did at the end?


3^-1 * 2 / 5 = 2/15
not 2/75. There is just a single z on the denominator. y^-11 on the numerator is equivalent to y^11 on the denominator, nothing else changes.
(edited 7 months ago)
Reply 10
Original post by mqb2766
3^-1 * 2 / 5 = 2/15
not 2/75. There is just a single z on the denominator. y^-11 on the numerator is equivalent to y^11 on the denominator, nothing else changes.


Ok thank you for all the replies!
Reply 11
Original post by subbhy
Ok thank you for all the replies!


It youre a bit unsure about this stuff, a simple tip is to write it all as multiplications, so division becomes multiplication by a reciprocal, so youre working with
(1/y)^2 (x^3)^2 (1/z^2)^2 (1/x)^3 (z)^3 (1/y^3)^3
then its easy to read off the relevant exponents for each base as per #2.
(edited 7 months ago)
Reply 12
Original post by mqb2766
It youre a bit unsure about this stuff, a simple tip is to write it all as multiplications, so division becomes multiplication by a reciprocal, so youre working with
(1/y)^2 (x^3)^2 (1/z^2)^2 (1/x)^3 (z)^3 (1/y^3)^3
then its easy to read off the relevant exponents for each base as per #2.


Yes I’ve got that thank you :smile:

Also, what do you think of the following problem?

I know you don’t have to actually work it out/try to work it out but disprove it by giving an example that doesn’t work
5316C7B9-BEE6-4D0F-86CF-83BC9438ECF0.jpg.jpeg
Reply 13
Original post by subbhy
Yes I’ve got that thank you :smile:

Also, what do you think of the following problem?

I know you don’t have to actually work it out/try to work it out but disprove it by giving an example that doesn’t work
5316C7B9-BEE6-4D0F-86CF-83BC9438ECF0.jpg.jpeg


Sounds like an interesting problem, youre starting the right way, so good luck.
Reply 14
Original post by mqb2766
Sounds like an interesting problem, youre starting the right way, so good luck.


Great thanks

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