What is the point of intersection of two lines, and how would I find it?

The point of intersection is where the lines would cross if we drew them on the same graph, in your exam you may be asked to find the coordinates of this point.

To do this we would first draw a sketch of the lines to see roughly where they meet, this will help us later to check our answer is right. Next rearrange the equation of one of the lines so it's in the form x= or y=. We then replace this value for x or y for that in the other equation, and simplify this to find a value for one of the coordinates. We use this coordinate to find out the other, and check these are what we'd expect from our graph.

For example, you could be asked 'Find the coordinates of the point of intersection of the lines x+2y-7=0 and 5x-y-2=0'.

From a sketch we can see that both coordinates should be positive.

Adding 7 to both sides of the first equation to get x+2y=7 and subract 2y to find x=7-2y.

Next substitute this into our other equation, so  5x-y-2=0 become 5(7-2y)-y-2=0 which simplfys to 33-11y=0 so y=3. Using this value we have 5x-3-2=0, so x=1.

These coordinates coordinates look right from out graph, and putting these values into the first equation x+2y-7=0 gives 1+6-7=0 which checks out.

So our final answer is that the point of intersection is  (1,3).

LS
Answered by Lisa S. Maths tutor

3491 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

-3<n<1 n is an integer, write down all the possible values of n.


How do I draw a straight line graph given a y=mx+c equation by the table method?


Solve the Simultaneous equation: 4x+y=25, x-3y=13


There are 11 pens in a box, 8 are black, 3 are red. Two pens are taken out at random without replacement. What is the probability the pens are the same colour?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences