The co-ordinates of P and Q respectively are (-9,7) and (11,12). M is on the line PQ such that PM:MQ = 2:3. L passes perpendicularly through M. What is the equation of L?

Draw a visual representation of P, Q, M and L.Work out the gradient of PQ to be 1/4.Know that the gradient of 2 lines perpendicular to each other multiplied is -1, therefore the gradient of L = -4. Work out the co-ordinates of M to be (-1,9).Know that y = mx + c where m = gradient and c = intercept.Substitute in the gradient of L and the co-ordinates of M to get c to equal 5.Answer: y = -4x + 5.