To solve the equation using complete square method we proceed: z^2-19z=66 but c=(-b/2a)^2 c=(-19/2)^2 c=361/4 thus: z^2-19z+361/4=66+361/4 factoring the LHS we get: 1/4(2z-19)^2=625/4
(2z-19)^2=625 getting the square root of both sides we get: 2z-19=+/-25 2z=+/-25+19 2z=44 or -6 z=22 or -3 Answer: z=22 or z=-3
