Question 28846
please help... 
using the point-slope formula, what is the equation of the line that passes through the points(1,5) and (0,0)
expalin how you got the answer

By formula the slope of the line joining 
two given points P(x1,y1) and Q(x2,y2) is given by
(y2-y1)/(x2-x1)
Therefore the slope of  the line joining  the points P(0,0) and Q(1,5) is
(5-0)/(1-0) = 5/1 = 5
[Here x1 = 0, y1 = 0 and x2 = 1,y2 = 5]
Here we have taken P to be the easier point (0,0)and the other point as Q. 
No loss of generality there!
The equation to a line in point-slope formula 
of a line passing through a fixed point P(x1,y1) and having slope = m 
is given by
(y-y1)/(x-x1) = slope
(y-0)/(x-0) = 5
y/x = 5   (here x1=0 and y1=0)
y =5x
Answer: y=5x  or 5x-y=0
Note: The equation that we have got for our line does not contain the free constant part. It contains only the x term and the y term. Why is this so?
It is because the line passes through the origin(0,))
The equation to any line passing through the origin is of the form    y = mx where m is the slope of the line.