<h3>
Answer: Choice H) 2</h3>
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Explanation:
Recall that the pythagorean trig identity is 
If we were to isolate sine, then,

We don't have to worry about the plus minus because sine is positive when 0 < x < pi/2.
Through similar calculations,
Cosine is also positive in this quadrant.
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So,

Therefore,

is an identity as long as 0 < x < pi/2
Part c : consecutive interior angle
part e: alternate interior angle
part f : vertical angle
Answer:
7x(3+2)=35x
add:
3+2=5
multiply:
7x(5)=35x
just using the distributive property, nothing more