Question 19623
again, you need to fit the numbers to y=mx+c


so...find the gradient, m
then find the value of c.


1. gradient... there is a definition of gradient that you will have in your books, concerning (change in y) divided by (change in x).


Use the 2 sets of coordinates in the Q to find the gradient of the straight line joining them up. The order you put the numbers into the equation for gradient doesn't matter. The answer is 0... note both coordinates have the same y-value... the line is horizontal, ie flat ie zero gradient.


So, this simplifies the equation of the straight line tremendously, to y = (0)x + c which is just y=c.


So, for c...

y = c pick eith set of coordinates..it doesn't matter (ever) and put the values in that you require: we need the y-value, which is -1, so we get c = -1


So, the equation of the line joing the 2 points quoted above is y = -1.


jon.