The general equation of a line is:

When m is the gradient and x1 and y1 are the coordinates of the points on the line
Therefore:


"x" always goes on the left side and "y" always goes on the right side of the parentheses. If you only have an "x" then you will just put a zero in for "y" and vice versa. I hope this helps.
The answer to Cindyelias82 question is 5.65685425i
Square Root (-2)+Square Root(-18)=5.65685425i