MixedHardQuestion 320014
Question
The circle x²+y²−6x−8y+9=0 is:
- AIntersected by x-axis at two points
- BTangent to x-axisCorrect
- CAbove the x-axis entirely
- DBelow x-axis
Correct answer
Tangent to x-axis
Explanation
Centre = (3,4), r = √(9+16−9) = √16 = 4. Distance from centre to x-axis = y-coordinate of centre = 4 = r. So the circle is tangent to the x-axis.