Please show the work so I can understand

Bring everything to the left side, but leave the -72

x^{2}+16x+y^{2}-6y=-72

Group x's and y's, then 'complete the square' by adding the square of half the coefficient of x and y.

(x^{2}+16x+64)+(y^{2}-6y+9)=-72+64+9=1

Factor each group:

(x+8)^{2}+(y-3)^{2}=1

That's it. It has center (-8,3) and radius=1

50-2x10+4

50-2x10+4

Straighten up.:rolleyes: