For the first question, simply find a point that is on the line segment. For the second question, knowing that in quadrant iii the x values are negative and the y values are also positive using this fact find the point that has x negative and y positive.
By changing the number into a decimal, and then moving the decimal twice to the right.
-5x(x+3)-7(x-3)/x^2-9= -5x^2-15x-7x+21/x^2-9= -5x^2-22x+21/x62-9