<span>Difference of squares method is a method that is used to evaluate the difference between two perfect squares.
For example, given an algebraic expression in the form:
can be factored as follows:

From the given expressions, the only expression containing two perfect squares with the minus sign in the middle is the expression in option A.
i.e.

which can be factored as follows:

.</span>
Speed of the east bound cyclist is 12 mph and the speed of west bound cyclist is 15 mph.
<u>Solution:</u>
Let us assume that x is speed of slower eastbound cyclist
So, x+3 will be the speed of faster westbound cyclist
We know that distance is the product of speed and time. That is,

West-bound DATA:
Rate of speed = x+3 mph ; Time = 6 hrs ; distance = 6(x+3) = 6x+18 miles
East-bound DATA:
Rate of speed = x mph ; time = 6 hrs. ; distance = 6x miles
On solving,
Distance apart = 162



So, the rate of speed of the east bound cyclist is 12 mph and the rate of speed of the west bound cyclist will be 
Answer:
r =2.9985yd
Step-by-step explanation:
Given that the circumference of a circle is 2
r
where r is the radius and
= 3.1415926....
You have
2
r = 18.84 yd
2(3.1415926)r = 18.84 yd
6.2831r = 18.84yd
divide through by 6.2831
r = 2.9985yd = aprox 3yds