Answer:

Step-by-step explanation:
Look at the picture.
ΔADC and ΔCDB are similar. Therefore the sides are in proportion:

We have

Substitute:
<em>cross multiply</em>


For x use the Pythagorean theorem:

The angles of a triangle always equal 180.
You do 180 - 80 - 45. X = 45.
Answer:
22x^2 -10xy + 12x
Step-by-step explanation:
To add and subtract polynomials, combine only like terms. When doing it vertically, stack polynomials and line up the same bases and exponents. Once this is done, simply add and subtract the coefficients.
10x^2 + 12xy + 4x
+ 12x^2 -22xy + 8x
_________________
22x^2 -10xy + 12x
Here we added 10 + 12 = 22, 12 + -22 = -10 and 4 + 8 = 12.
<span>(a.)
Let's say α is the angle that subtends from the top of the screen to horizontal eye-level.
Let β be the angle that subtends from the bottom of the screen to horizontal eye-level.
tanα = (22 + 10 - 4) / x = 28/x
α = arctan(28/x)
tanβ = (10 - 4) / x = 6/x
β = arctan(6/x)
Ɵ = α - β
Ɵ = arctan(28/x) - arctan(6/x)
(b.)
tanƟ = tan(α - β) = (tanα - tanβ) / (1 + tanα tanβ)
tanƟ = (28/x - 6/x) / [1 + (28/x)(6/x)]
tanƟ = (22/x) / [1 + (168/x²)]
tanƟ = 22x / (x² + 168)
Ɵ = arctan[22x / (x² + 168)]</span>