3. write an equation for the circle whose center is at (9,0) and has radius 7.

x²+y²-18x+81-49= 0

Step-by-step explanation:

For a circle with radius (r) and b center (a,b), the general form of the circle will be;

(x-a)²+(y-b)² = r²

According to the question, center given is (9,0) and radius is 7

From the value of the center,

a = 9 b = 0

Substituting this values into the general equation of the circle, this gives;

(x-9)²+(y-0)² = 7²

x²-18x+81+y² = 49

Re arranging

x²+y²-18x+81-49= 0 which gives the required equation.

what is the model?

step-by-step explanation: