Using the method of completing the square, put each circle into the form

then determine the center and radius of each circle

Standard form:

Center:

Radius:

Step-by-step explanation:

The equation of a circle in the standard form is

Where the point (h, k) is the center of the circle

To transform this equation this equation  in the standard form we use the method of square.

First, we group similar variables

Divide both sides of equality by 4

Now we complete square for variable x.

Take the coefficient "b" that accompanies the variable x and divide by 2. Then, elevate the result to the square:

Now add on both sides of the equality

Factor the expression and simplify the independent terms

Then

and the center is

radius

(3x-8) or (3x+8)

step-by-step explanation:

54 kilometers per hour

step-by-step explanation:

according to rules:

1 km = 1000 meter

which means that 1 meter = 1/1000 km

1 hour = 3600 second [ as 1 hour = 60 min = 60 *60 seconds ]

which means that 1 second = 1/3600 hour

therefore, 1 kilometer/hour =

thus to convert 15 meter per second to kilometer per hour, we multiply 15 to 3.6 kilometer/hour.

15 meter/second=   which is the required answer.