# A level maths straight lines question

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#1
i cant see whats gone wrong here please could someone have a look

i first worked out the grad in terms of p, and formed a straight line equation. then i subbed in the coordinates of A and got the value of p=-1/3 which is wrong
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1 month ago
#2
(Original post by vix.xvi)
i cant see whats gone wrong here please could someone have a look

i first worked out the grad in terms of p, and formed a straight line equation. then i subbed in the coordinates of A and got the value of p=-1/3 which is wrong.
Unless I'm mistaken, you've got a sign error between the line where you have 2p on one side and 8p on the other and the line where your replace that by 6p.
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1 month ago
#3
(Original post by DFranklin)
Unless I'm mistaken, you've got a sign error between the line where you have 2p on one side and 8p on the other and the line where your replace that by 6p.
Yeah that's what I think
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1 month ago
#4
(Original post by vix.xvi)
i cant see whats gone wrong here please could someone have a look

i first worked out the grad in terms of p, and formed a straight line equation. then i subbed in the coordinates of A and got the value of p=-1/3 which is wrong
You've changed the sign of 6p on the left but then changed both the numerator AND denom on the right - you need to only change the numerator.
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1 month ago
#5
(Original post by DFranklin)
Unless I'm mistaken, you've got a sign error between the line where you have 2p on one side and 8p on the other and the line where your replace that by 6p.
They x by -1 on the left but done that to the numerator and denom on the right.
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#6
(Original post by Muttley79)
You've changed the sign of 6p on the left but then changed both the numerator AND denom on the right - you need to only change the numerator.
sorry this sounds rly stupid but why only the numerator? if you multiply the entire thing by -1, then each sing (unless multiplied), changes right? x
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1 month ago
#7
(Original post by vix.xvi)
sorry this sounds rly stupid but why only the numerator? if you multiply the entire thing by -1, then each sing (unless multiplied), changes right? x
-2/(-2) = 1 = 2/2
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1 month ago
#8
(Original post by vix.xvi)
sorry this sounds rly stupid but why only the numerator? if you multiply the entire thing by -1, then each sing (unless multiplied), changes right? x
No - if you multiply both you've multiplied by 1 not -1
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#9
(Original post by mqb2766)
-2/(-2) = 1 = 2/2
thank youuu

(Original post by Muttley79)
No - if you multiply both you've multiplied by 1 not -1
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