A ) cos² x · 1 / sin x - 1 / sin x = - sin x
cos² x - 1 / sin x = - sin x
- sin² x / sin x = - sin x
- sin x = - sin x ( correct )
B ) sin x ( cos x / sin x + sin x / cos x ) = 1 / cos x
sin x · ( cos² x + sin²x ) / sin x cos x = 1 / cos x
sin x · 1 / sin x cos x = 1 / cos x
1 / cos x = 1 / cos x ( correct )
C ) cos² x - sin² x = 1 - 2 sin² x
1 - sin² x - sin² x = 1 - 2 sin² x
1 - 2 sin² x = 1 - 2 sin² x ( correct )
D ) 1/sin²x + 1/ cos²x = 1
cos²x + sin² x / sin² x cos² x = 1
1 / cos² x sin² x = 1
cos²x sin² x ≠ 1
Answer: D ) is not an identity.
An equation is formed of two equal expressions. The solution of the equation is w=3.
<h3>What is an equation?</h3>
An equation is formed when two equal expressions are equated together with the help of an equal sign '='.
In order to solve the equation, we need to isolate the variable in the following manner, therefore, the solution of the equation can be written as,

Divide both sides of the equation by 6.2,

Hence, the solution of the equation is w=3.
Learn more about Equation:
brainly.com/question/2263981
Answer: 20d + 5
Step-by-step explanation:
First we need to combine like terms.
In this equation we can see that they're are 3 numbers containing the letter D we have -4, -4, 28.
We're going to combine -4 and -4 to get -8 and then combine -8 to 28 getting 20d
Afterwards we're going to combine 3, 2 equaling 5.
Let's say that ST is side b
<span><span>Use the Law of Sines to find side b.</span><span>
b / sin(B) = a / sin(A)</span><span>
b / sin(59°) = 7 / sin(79°)</span><span>
b = (sin(59°) x 7) / sin(79°)</span><span>
b = 6.112
That is answer B.) 6.1 yards
Hope this helps!</span></span>
Answer:
11
Step by step explanation:
2x4=8
8+3=11