Answer:
(6,1)
Step-by-step explanation:
1.) group the x and y terms (and move the constant to the other side)
x²-12x+y²-2y= -12
divide the coeficcents for the terms with just 1 or 1 x variable by 2 and then square it (and add that to both sides)
x²-12x+36+y²-2y+1= -12+36+1
factor
(x-6)²+(y-1)²= 25
the center is therefore (6,1)
The line needs to be 8.06 m long
Explanation
Given that the ladder is 7 feet tall and the bottom of the slide should be 4 m away from the ladder.
The ladder,slide and the ground connecting them makes the sides of a right angled triangle with ladder as the height and ground as the base.
base=4m
height=7m
hypotenuse can be determined using pythagoras law

If you find a first you will be able to find b a little faster then it is super easy after that you got this!
First subtract the x variable on both sides so on the first equation youll have -6y=8x+60 then divide 6 on all variables which means youll have y=8/6x+10 and in the second equation you do the same thing and youll have y=-5/6x-11.5