Question

Consider a circle whose equation is x2 + y2 – 2x – 8 = 0. Which statements are true? Select three options. The radius of the circle is 3 units. The center of the circle lies on the x-axis. The center of the circle lies on the y-axis. The standard form of the equation is (x – 1)² + y² = 3. The radius of this circle is the same as the radius of the circle whose equation is x² + y² = 9.

Answer 1

The center of the circle lies on the x-axis.
The radius of the circle is 3 units.

The radius of this circle is the same as the radius of the circle whose equation is x² + y² = 9.

The standard equation of a circle is expressed as: Centre is (-g, -f)radius = √g²+f²-CGiven a circle whose equation is Get the centre of the circle2gx = -2x2g = -2g = -1Similarly, 2fy = 0f = 0Centre = (-(-1), 0) = (1, 0)This shows that the center of the circle lies on the x-axisr = radius = √g²+f²-Cradius = √1²+0²-(-8)radius =√9 = 3 unitsThe radius of the circle is 3 units.

For the circle x² + y² = 9, the radius is expressed as:r² = 9r = 3 units Hence the radius of this circle is the same as the radius of the circle whose equation is x² + y² = 9.