Answer:
Yes, any pair of complementary angles add up to 90 degrees. By simply using 90-x you can find the other angle.
Find slope (y2-y1)/(x2-x1)
Pick points: (1,10) , (2,8)
(8-10)/(2-1) = -2/1 = -2
Y = -2x + b
10 = -2 + b, b = 12
It would be the first response
12 = initial while -2 is rate of change
Answer:
Part 1) 
Part 2) 
Step-by-step explanation:
The picture of the question in the attached figure
Part 1
Find the length side AB
we know that
----> by SOH (opposite side divided by the hypotenuse)
substitute the given values

solve for AB

Part 2
Find the length side AC
we know that
----> by TOA (opposite side divided by the adjacent side)
substitute the given values

solve for AC

Consider a trapezoid GJKF with:
GH=JH (hypothesis)
FL=KL (hypothesis)
so HL is the median of trapezoid GJKF
so: HL=1/2(2.5+1.2)=1.85
Cos -2x or -cos2x, it's the difference.