Hello,
(x2−4x+y2−6y−36=25),
(x2−4x−y2−6y=25+36),
(x2−4x+y2−6y=61),
(x2−4x+?+y2−6y=61+?),
to solve the equation x2−4x+4=(x−2)2,
we are adding 4:
(x2−4x+4+y2−6y=61+4),
factorise the expression using square of a binomial (a2−2ab+b2=(a−b)2),
(x−2)2+y2−6y=61+4
(x−2)2+y2−6y=65,
(x−2)2+y2−6y+?=65+?,
to solve the equation y2−6y+9=(y−3)2,
we are adding 9:
(x−2)2+y2−6y+9=65+9,
factorise the expression using square of a binomial a2−2ab+b2=(a−b)2,
(x−2)2+(y−3)2=65+9,
(x−2)2+(y−3)2=74,
The equation can be written in the form (x−p)2+(y−q)2=r2
so that it corresponds to a circle with radius (r=√74) and centre (2,3).
Straight