Question 1:
Draw it (or just look at the image).
In the image, I solved for the last angles.
The triangles are congruent by ASA and RT is congruent to FD
The first choice is your answer.
Question 2:
We have an isosceles triangle.
Angle STR = 180 - Angle STU
Angle STR = Angle SRT = 180 - 8x
7x - 54 + 2(180 - 8x) = 180
-9x = -126
x = 14
The answer is the first choice.
Question 3:
The HL theorem is in order for two right triangles to be congruent, one pair of legs and a pair of hypotenuses must be congruent.
AC = DC (third choice)
OR
BC = CE (no matches)
The third choice is your answer.
Have an awesome day! :)