You are Here: Home >< Maths

# core1 - point of intersection question

1. Find the co-ordinates of the point of intersection between the line y=5-x and the curve xy=-4.
so far , i substituted y=5-x into the equation xy=-4 to get: -x^2+5x+4=0
then i completed the square since i couldnt factorise that. and the x cordinate from the completing the square was 5/2. what do i do after this to find the points of intersection?
2. (Original post by Chelsea12345)
Find the co-ordinates of the point of intersection between the line y=5-x and the curve xy=-4.
so far , i substituted y=5-x into the equation xy=-4 to get: -x^2+5x+4=0
then i completed the square since i couldnt factorise that. and the x cordinate from the completing the square was 5/2. what do i do after this to find the points of intersection?
Firstly, there are two point of intersection so you need 2 x-coordinates that you get from solving the quadratic.

Secondly, you must've completed the square correctly, but you did not solve for x.

Thirdly, once you have the two x-coordinates, subtitute them into the line equation to get your y-values.
3. (Original post by Chelsea12345)
Find the co-ordinates of the point of intersection between the line y=5-x and the curve xy=-4.
so far , i substituted y=5-x into the equation xy=-4 to get: -x^2+5x+4=0
then i completed the square since i couldnt factorise that. and the x cordinate from the completing the square was 5/2. what do i do after this to find the points of intersection?
You should obtain the quadratic .
You should find the x coordinates and then sub these x values to find y to find the coordinates a of intersection.

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
your full birthday is required
1. Oops, you need to agree to our Ts&Cs to register

Updated: October 19, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### Why should I go to work...

...when I could get more on benefits?

Poll
Useful resources

## Make your revision easier

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

Can you help? Study help unanswered threads

## Groups associated with this forum:

View associated groups
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.