What is the equation of a straight line passing through two points?

[jahlin]

Homework Statement

whats the equation of a straight line passing through (1,4) and (5,1)?

Homework Equations

y=mx+c

The Attempt at a Solution

i found the equation to be y=-(3/4)x is it right?
Thanks

 

[Dick]

No it's not right. How did you get y=(-3/4)x? The slope is right. The c part isn't.

 

[jahlin]

well it doesn't intercept with the y-axis so i assumed it to be zero..

 

[weesiang_loke]

hi
actually the straight line intercepts with y-axis. you can substitute the x value and y value into the equation you found. Obviously they cannot fit.
so the gradient you get is -3/4, which is the correct one.
y = (-3/4)x + c;
one way to find c is by substituting (1, 4) into equation stated above.
then the correct equation of the straight line passing through two points can be found.

Cheers,
weesiang_loke