Find the equation of circle of radius 3, passing through the origin and having its centre on the x-axis.

Explanation

To find the equation of a circle of radius 3 that passes through the origin and has its center on the x-axis, we can follow these steps:

### Step 1: Define the center of the circle
Since the center of the circle lies on the x-axis, we can denote the center as \( (h, 0) \).

### Step 2: Use the distance formula
The radius of the circle is given as 3, and since the circle passes through the origin (0, 0), we can use the distance formula to set up our equation. The distance from the center \( (h, 0) \) to the origin \( (0, 0) \) must equal the radius:

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