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Coordinate Geometry - A-level Mathematics

I'm stuck on this HW question. I got upto part d) then my calculator said the final answer had no real roots. Can anyone tell me if I did anything wrong. Attached images below:
Reply 1
Original post by r_g1452
I'm stuck on this HW question. I got upto part d) then my calculator said the final answer had no real roots. Can anyone tell me if I did anything wrong. Attached images below:

For the first part a, b and c should be integers. Your a is -1/4 so you need to ... A minor point, Id have taken everything over to the left so that a and b were positive, so only a single term was negative.

For the area, its two simple marks and there is no need to do heron. Just think (not too hard) about another way to get the area using the answers to parts b) and c). But your triangle lengths have errors. OA must be 52, which in turm is a bit of a hint about the way to go.
(edited 2 months ago)
Original post by r_g1452
I'm stuck on this HW question. I got upto part d) then my calculator said the final answer had no real roots. Can anyone tell me if I did anything wrong. Attached images below:

Note that part (b) asks for the coordinates of the point where L1 crosses the y-axis, not the x-axis.
(edited 2 months ago)
Reply 3
@old_engineer
@mqb2766
Thanks for the response.
Taking into account what both of you've said. I got OA as 13 and to find the area it was (bxh)/2 which was 26. Would that be right?
Wroking out here:
https://ibb.co/0qYGJYx
(edited 2 months ago)
Reply 4
Original post by r_g1452
@old_engineer
@mqb2766
Thanks for the response.
Taking into account what both of you've said. I got OA as 13 and to find the area it was (bxh)/2 which was 26. Would that be right?
Wroking out here:
https://ibb.co/0qYGJYx

Looks about right. Some minor stuff

β€’

no need to calc the lengths in d)

β€’

in d) you only /2 on the second line, A is not the triangle area on line 1

β€’

in a) you could start with y-y1 = m*(x-x1) as its a standard line representation

β€’

in a) end Id get in the habit of making two positive coefficients, so multiply through by -1

β€’

b) is a write down, no working should be necessary.

β€’

in c) you go back to working with fractions for "a". Not wrong, but unnecessary.

Reply 5
Original post by mqb2766
Looks about right. Some minor stuff

β€’

no need to calc the lengths in d)

β€’

in d) you only /2 on the second line, A is not the triangle area on line 1

β€’

in a) you could start with y-y1 = m*(x-x1) as its a standard line representation

β€’

in a) end Id get in the habit of making two positive coefficients, so multiply through by -1

β€’

b) is a write down, no working should be necessary.

β€’

in c) you go back to working with fractions for "a". Not wrong, but unnecessary.


Right ok, Thank you . πŸ™

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