X= + or- square root 66 i solved using the pq formula but u can also use the quadratic formula as well and the square root formula but I'ma show u how to solve it with pq it's on this image hope it helps and mark me brainliest
No ❤️ hahaha i can’t see anything

Step-by-step explanation:
We know that
cos 2x = 2cos²x - 1
So we have

Substituting 

Answer:
7) 49°
8) 77°
9) 87°
10) 135°
Step-by-step explanation:
7) The angles are between the parallel lines, so are "interior." They are on opposite sides of the transversal, so are "opposite interior" angles. Such angles are congruent, so ...
... ? ≅ 49°
8) The angles are adjacent interior angles, so are supplementary.
... ? + 103° = 180°
... ? = 77°
9) The angles are outside the parallel lines, so are "exterior." They are on opposite sides of the transversal, so are "opposite exterior" angles. Such angles are congruent.
... ? ≅ 87°
10) These are vertical angles, so are congruent. (The other parallel line is irrelevant and doesn't need to be there for this relationship to be true.)
... ? ≅ 135°
Answer:
right angle triangle
Step-by-step explanation: