A straight line makes on the coordinate axes positive intercepts whose sum is 7. If the line passes through the point (-3, 8), find its equation.

If the coordinates of the vertex A of a square ABCD are (3, -2) and the equation of diagonal BD is 3x - 7y + 6 = 0, find the equation of the diagonal AC. Also find the coordinates of the centre of the square.

Find the equation of a line parallel to 2y = 6x + 7 and passing through (-1, 1)

A line segment joining P (2, -3) and Q (0, -1) is cut by the x-axis at the point R. A line AB cuts the y-axis at T(0, 6) and is perpendicular to PQ at S. Find the :

(a) equation of line PQ

(b) equation of line AB

(c) coordinates of points R and S.