Question 38452
look at the lessons i have written on this topic. They will help you.


Anyway...
a straight line is of the form y=mx + c. We need to find the value of m (the gradient) and c (the y-intercept).


Right then. Gradient first.
gradient, m = (change in y)/(change in x)
{{{ m = (3 - (-2))/(-1 - 4) }}}
{{{ m = (3+2)/(-5) }}}
{{{ m = (5)/(-5) }}}
--> m = -1


so we now have y=-x+c


Now for c: we need to know x and y to find c. We do...we have 2 possible pairs of x and y: the 2 sets of coordinates. Pick the "easiest" pair. I will pick (-1,3):


y=-x+c
3=-(-1)+c
3 = 1+c
2 = c


--> equation is y=-x+2


AND  NOW CHECK WITH THE OTHER SET OF COORDINATES, here (4,-2): if we put x=4 into the equation, we shout get y=-2 out of it:


y=-x+2
y=-4+2
y = -2... CORRECT


so now i KNOW i am correct


jon.