Answer:
Choice B is correct.
Explanation:
The given equation is -r+5(r+2)=-10
Put r=-5 into the above equation
-(-5)+5(-5+2)=-10
5+5(-3)=-10
5-15=-10
-10=-10
Right and left side of above equation is equal by putting r=-5 so it is true statement.
Answer:

Step-by-step explanation:
As we are given the adjacent (a) side and the hypotenuse (h), we can use the cosine function to find the measure of angle B.
Recall that 
This means that in order to find B, we need to take the inverse of cosine
This gives us

From a calculator, we find that the answer of this is

When this is rounded to the nearest hundredth, we get

Answer:
y = 5 ft
Step-by-step explanation:
We are looking for y.
This is a right triangle, so we can use the Pythagorean theorem
a^2 + b^2 = c^2 where a and b are the legs and c is the hypotenuse
a = 12 and b = y c = 13
12^2 + y^2 = 13^2
144 + y^2 =169
Subtract 144 from each side
144-144 +y^2 = 169-144
y^2 = 25
Take the square root of each side
sqrt(y^2) = sqrt(25)
y = 5