So based on your question where there is a rectangle inscribed in a semicircle or a radius 10 as shown in your figure. The possible function that could represent the are of the rectangle is A=2x*sqrt(100-x^2) i hope you are satisfied with my answer and feel free to ask for more
Charles' weight = Edith's weight + 20% of Edith's weight
We'll use a variable to represent Edith's weight, x.
The decimal form of 20% is 0.2.
60 = x + 0.2x
60 = 1.2x
x = 50
Edith's weight is 50kg.
Hope this helps!
The answer is 8x.
You are combining like terms as 5 and 3 both have x so you are simply adding 5+3= 8
Let
A-----> 
B-----> 
C-----> 
we know that
Point A-------> Multiply numerator and denominator by 

Point B-------> Multiply numerator and denominator by 

Point C-------> Multiply numerator and denominator by 

Find the distance Point A to Point C

Find the distance Point B to Point C

therefore

Point B is closer to Point C
is closer to 
the answer is
is closer to 
B because that is where they intersect