Question

Find the center and radius of x^2 – 18x + y^2 -10y = -6. part two write x2 – 18x + y2 -10y = -6 in standard form

Answer 1

see explanation

Explanation:

I will begin with part two, first.

The equation of a circle in standard form is

(x - h)² + (y - k)² = r²

where (h, k) are the coordinates of the centre and r is the radius.

Given

x² - 18x + y² - 10y = - 6

Using the method of completing the square

add ( half the coefficient of the x/ y terms )² to both sides

x² + 2(- 9)x + 81 + y² + 2(- 5)y + 25 = - 6 + 81 + 25, that is

(x - 9)² + (y - 5)² = 100 ← in standard form

with centre = (9, 5 ) and r =
`√(100)` = 10