You may want to have a look at Translating
Lines and Reflecting
Lines before working on this problem.

Think about what happens to the intercept and gradient after each transformation.

How can I combine these transformations so that the gradient stays the same and the intercept moves down 9 places?

Think about what happens to the intercept and gradient after each transformation.

How can I combine these transformations so that the gradient stays the same and the intercept moves down 9 places?