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# Could someone explain what's wrong in solving this simultaneous equation?

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1. Could someone explain why the first try is incorrect and the second one is right (according to the mark scheme)?

Sorry for messy handwriting, after 5h of doing questions my hand is starting to deform.
2. (Original post by frostyy)

Could someone explain why the first try is incorrect and the second one is right (according to the mark scheme)?

Sorry for messy handwriting, after 5h of doing questions my hand is starting to deform.
I'm confused, you've written two different simultaneous equations down?

For the first block, is correct and this gives you . This is correct.
3. (Original post by frostyy)

Could someone explain why the first try is incorrect and the second one is right (according to the mark scheme)?

Sorry for messy handwriting, after 5h of doing questions my hand is starting to deform.
-120 + - 45 =/= -75.
4. (Original post by frostyy)

Could someone explain why the first try is incorrect and the second one is right (according to the mark scheme)?

Sorry for messy handwriting, after 5h of doing questions my hand is starting to deform.
In the second one just check the -120 + -45
5. (Original post by kingaaran)
-120 + - 45 =/= -75.
You beat me to it.
6. (Original post by maggiehodgson)
You beat me to it.
7. (Original post by kingaaran)
-120 + - 45 =/= -75.

the answer to a) is 4y - 3x - 15 = 0

according to the mark scheme, in b), x = 3

wtf?
8. (Original post by frostyy)

the answer to a) is 4y - 3x - 15 = 0

according to the mark scheme, in b), x = 3

wtf?
Hmm, in your second bit of working, have you copied down the equation correctly?

Edit: And in the first one for that matter?
9. (Original post by frostyy)
the answer to a) is 4y - 3x - 15 = 0

according to the mark scheme, in b), x = 3

wtf?
Yes, that's correct. Why?

Your second equation should either be or .
10. (Original post by frostyy)

the answer to a) is 4y - 3x - 15 = 0

according to the mark scheme, in b), x = 3

wtf?
in your first workings you are not using 4y - 3x -15, I think
11. Thank you for all the help.

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