1. Find the slope of the line that passes through the points (-1 , 0) and (3 , 8). 2. Find the slope of the line that passes through the points (2 , 0) and (2 , 4). 3. Find the slope of the line that passes through the points (7 , 4) and (-9 , 4). 4. Are the three points A(2 , 3) , B(5 , 6) and C(0 , -2) collinear? 5. What is the slope of the line parallel to the line whose equation is given by -y = - 2 x + 4? 6. What is the slope of the line perpendicular to the line whose equation is given      by - 2y = - 8 x + 9? 7. Is the triangle whose vertices are the points A(0 , -1) , B(2 , 1) and C(-4 , 3) a right triangle? 8. What is the slope of the line -7y + 8x = 9 9. What is the slope of the line y = 9? 10. What is the slope of the line x = -5?