What is the equation of the line that is perpendicular to and has the same y intercept as the given line?

How do you solve a question like this?

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.

The statements below can be used to prove that the triangles are similar. ? △abc ~ △xyz by the sss similarity theorem. which mathematical statement is missing? ∠b ≅ ∠y ∠b ≅ ∠z