Question

Find radius and centre of the circle x^2+y^2-8x-12y+15=0

Answer 1

Answer

a=-4 b=+6 and r= root-5

Step-by-step explanation:

x^2+y^2-8x-12y+15=0

let

(x-a)^2+(y-b)^2=r^2

x^2+8x+y^2-12y= -15

x^2 + 2(4)x + y^2(-6)y = -15

[x^2 + 2(4)(x)+(4)^2-(4)^2] +[y^2-2(-6)(y)+(-6)^2(-6)^2]=-15

[x^2 + 2(4)(x)+(4)^2] +[ y^2+2(-6)(y)(-6)^2]-(4)^2-(-6^2)=-15

Then, By using the formula (a+b)^2=a^2+b^2+2ab

(x+4)^2+(y+6^2)= 16-36=-15

=+15+16-36

= 31-36

(x-(-4))^2+(y-(6))^2 =-5

Therefore

(x-a^2) +(y-b^2)=r^2

then,

a= -4 ;b= +6 & r = root -5

I hope this is the ans ur looking for and I hope its correct ans

Answer 2

I hope this will helpful to you