A)
x^2 - 6x + c = - 5 + c
using a^2 - 2ab + b^2 = (a-b)^2
so
6x = 2 * x * 3
so
c = 9
Answer
c = 9
b)
substitute c = 9
x^2 - 6x + 9 = - 5 + 9
(x - 3)^2 = 4
Answer:
(x - 3)^2 = 4
c) solve for x
(x - 3)^2 = 4
(x - 3)^2 = 2^2
so
x - 3 = 2
x = 5
and
x - 3 = -2
x = 1
Answer: x = 1 , 3