Hey there!!
The answer is multiplicative identity.
Hope my answer helps!!
Answer:

Step-by-step explanation:
Given that x and y are proportional and the equation relating them is
y = rx ← r is the constant of proportionality
To find r use any ordered pair from the table
Using x = 9, y = 4.5 , then
4.5 = 9r ( divide both sides by 9 )
= r , that is
r = 
The answer is A
You can solve this by equation the two equations, by substitution method or elimination. Let's choose the substitution since Equation 2 has already X isolated
-take the X in equation 2 and substitute in the first equation
So, You should have 5 (5-3/2 y) -4y =7
Get y ( I'll assume you know how to simplify and find y by yourself )
y=36/23
-Now take y and substitute it in the first equation or the second equation (it doesn't really matter)
Substituting y in Equation 2:
x=5- 3/2 (36/23)
=> x= 61/23
So answer is A where (x,y) is (61/23, 36/23)
Option C: 90° is the value of x.
Explanation:
The given expression is
for 
We need to solve the expression.
Thus, we have,

Subtracting both sides by 4, we have,

Adding both sides by 8 sin x, we get,

Dividing both sides by 10, we have,

Taking
on both sides of the equation, we get,


Thus, the value of x is 90°
Hence, Option C is the correct answer.