Question

How do you write the equation for a circle with a center (-5,4); tangent (touching at one point) to the x-axis?

Answer 1

`x^2+y^2+10x-8y+25=0`

Explanation:

`r=4` because the circle is tangent to the x-axis
therefore the equation is:

`(x+5)^2+(y-4)^2=16`

`x^2+10x+25+y^2-8y+16-16=0`

`x^2+y^2+10x-8y+25=0`