Find the equation of the circle with centre (-9,0) and radius root a�

1.	Find the equation of the circle with centre (-9,0) and radius root a
Answer» Answer: Equation of circle: $x^{2} + y^{2} +18x + 81 - a = 0$ Step-by-step explanation: Centre coordinates = (-9,0) = (h,k) .: where h = -9 and k = 0 Radius = $\sqrt{a}$ = r We know, the general equation of circle is $(x - h)^{2} + (y - k)^{2} = r^{2}$ So, INSERTING the values in the equation, we GET $(x - (-9))^{2} + (y - 0)^{2} = (\sqrt{a} )^{2}\\(x + 9)^{2} + (y)^{2} = a\\x^{2} +18x +81 + y^{2} = a\\x^{2} + y^{2} +18x + 81 - a = 0$ So, the equation of circle is $x^{2} + y^{2} +18x + 81 - a = 0$ PLEASE MARK IT THE BRAINLIEST