Question

Write the equation of the sphere in standard form. x2 + y2 + z2 + 4x − 6y − 6z = −6

Answer 1

Hello : 
x2 + y2 + z2 + 4x − 6y − 6z = −6
(x²+4x) +(y² - 6y) +( z² -6z) = -6
((x² +4x +4) -4 ) + ((y² - 6y +9) - 9 ) + ((z² - 6z+9) -9 ) = - 6 
(x+2)² + (y - 3)² + ( z - 3)² = 4²...( standard form )