How do I find the equation of a line between two points?

The equation of a line is written in the form y=mx+c where m is the gradient of the line and c is the y-intercept. These are the two values that we will need to calculate.For example, lets take the two points (2,2) and (6,4). We will label the two coordinates so that (2,2) is no.1 and (6,4) is no.2.To find the gradient, or slope, of the line we use the formula m=(y2-y1)/(x2-x1) where x1 is the x coordinate of no.1 and so on. Therefore, m=(4-2)/(6-2)= 1/2So we can now update our equation y=mx+c by substituting the m value to give y=0.5x+cTo find the c value, or the y-intercept, we then take one of our coordinates (either will work!)So for example, taking no.1, (2,2) and using x=2 and y=2 we can put this into our updated equation y=0.5x+c to give 2=(0.52)+cSolving this for c we get c=1 and then putting this into our equation we get y=0.5x+1 which is the line equation needed.

Answered by Lucille R. Maths tutor

3047 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Marcin buys 7 rulers and 15 crayons for £7. A ruler costs 12p more than a crayon. Find the cost of one crayon.


Tom starts with 50 balls. Amy starts with 28 balls. If Tom gives 22 balls to Amy, what percentage of balls does Tom have compared with Amy?


What is the correct answer if you rearrange the following, making "c" the subject? (3c+b)/2 = c + a


If Angela gets 50p change from a £2 coin, how much is 250g of butter? (full details below)


We're here to help

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