Circle Question no. 16 Under which of the following conditions does a general equation ax 2 + 2hxy + by 2 +2gx +2fy +c = 0 represents a circle? looks_one h=g , a=b looks_two h=g=f , a=b looks_3 h=0 , a=b looks_4 h=0 , g 2 + f 2 -c=a+b Answer Option looks_3 h=0 , a=b Solution Solution : Condition for circle 1) a = b 2) h = 0 Question no. 17 What is the equation to circle which touches both the axes and has centre on the line x+y-4=0 ? looks_one x 2 + y 2 +4x -4y +4 = 0 looks_two x 2 + y 2 +4x +4y +4 = 0 looks_3 x 2 + y 2 -4x -4y +4 = 0 looks_4 x 2 + y 2 -4x +4y +4 = 0 Answer option looks_3 x 2 + y 2 -4x -4y +4 = 0 solution Solution : x+ y = 4 If both the axes are touched by circle (x-2) 2 + (y-2) 2 = 4 x 2 + y 2 -4x -4y +4 = 0 Question no. 18 If the Circle x 2 + y 2 +2gx +2fy +c = 0 (c>0) touches the y-axis , then which one of the following is correct ? l...