Answer:

Step-by-step explanation:
Given

Required
Determine the solution
Since b is a perfect square, the equation can be expressed as:

Apply difference of two squares:

Split:

Remove brackets:

Make a the subject in both equations

The solution can be represented as:

Answer:
10.5
Step-by-step explanation:
because 10.5x2=21. and 45+13+21=79, 100-79= 21.
Answer:
Option A
Step-by-step explanation:
Given:
Center of circle = (h,k)= (3,8)
Radius = r = 5
The standard form of equation of circle with center and radius is:

Therefore, the general form of the equation of circle given is:

Hence, option A is correct ..
Answer:
x=15
Step-by-step explanation: