Please help with this math work!! Solve for x , Assume which appear tangent are tangent

Which of the following is the result of expanding

If the altitude is drawn to the hypotenuse of a right triangle, then the two triangles formed are similar to the original triangle and to each other. which set of triangles shows the similar triangles created by the altitude in the diagram?

X² + 4y² = 36 the major axis runs along: a) y=4x b) x-axis c) y-axis