Find the equation of the line in the form of y=mx+c given that two points on the line are (3,1) and (6,10)

Firstly, we can solve this equation by drawing a graph. By drawing it accurately we can see that the line intercepts the y-axis at -8 making the c value = -8. Next to calculate the gradient, m, we can take any two points on the line, in this case I will take (0,-8) and (3,1). The gradient is the change in y divided by the change in x. 1-(-8)=9 which is the change in y and 3-0 is the change in x. 9/3=3 which is the m value. So the equation of the line is y=3x-8.We can also solve this algebraically. Similarly to find the gradient, we can take the two coordinates which have been given to us, (3,1) and (6,10) and find the difference in y divided by the difference in x. 10-1=9 which equals the change in y and 6-3=3 which equals the change in x. 9/3 is 3 so m=3. We can then use these values to find c. By substituting one of the coordinates into our y=mx+c equation, (3,1) in this case, we get 1=3(3)+c. This simplifies to 1=9+c so c=-8. This method can be used to solve any linear equation from two points.

Samuel I. avatar
Answered by Samuel I. Maths tutor

4071 Views

See similar Maths GCSE tutors
Cookie Preferences