Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
Find the line through the meeting point of and that also passes through . Give the coordinates of the meeting point, and the -intercept of the required line.
The lines through the meeting point of and are , except itself. To find the fixed point of a family with a letter , collect the terms with and solve the two brackets together. Three lines are concurrent when the meeting point of two lies on the third. Shifting the origin to puts and .
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The meeting point. From the second equation . Then , so and .
Step 2. Find . At : , so and .
Step 3. The line. gives , which is .
Step 4. The -intercept. With : .
Answer: the lines meet at . The required line is , with -intercept .
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