Question

What is the circle with center (5, -6) tangent to the y axis?

Answer 1

Tangent to the y axis means the radius to the y axis must be perpendicular to the axis, so `(0,-6)` is on the circle; so it has a radius of 5, and equation

`(x-5)^2+(y+6)^2=5^2`

Explanation:

graph{0=( (x-5)^2+(y+6)^2-5^2 )( (x-5)^2+(y+6)^2-.1^2 ) [-4.74, 15.26, -8.76, 1.24]}