I've done this question in a completely different way:

1. Draw a sketch of the lines

and

and the point A.

2. Determine the point of intersection of a and b:

3. Determine the equation of a line parallel to a through A

4. Determine the point of intersection of p and b:

5. You reach S if you go from R 2.2 units right and 2.2 units down. Now go from S 4.4 units right and 4.4 units down and you are at Q:

.

6. Determine the equation of the line AQ = l:

. Determine the point of intersection of

7. I've got