Answer:
a. two (distinct) real solutions.
c = 3, x=¨{-1,-3}
b. two complex solutions
c = 17, x={-2+sqrt(13)i, -2-sqrt(13)i}
c. two coincident roots (i.e. one real solution)
c=4, x = {-2}, or x = {-2, -2}
Step-by-step explanation:
Given:
x^2+4x+c =0
a. two (distinct) real solutions.
c = 3
(x+1)(x+3) = 0
x=¨{-1,-3}
b. two complex solutions
c = 17
x^2+4x+17=0
does not have real factors.
x={-2+sqrt(13)i, -2-sqrt(13)i}
c. two coincident roots (i.e. one real solution)
c=4
x^2+4x+4=0 => (x+2)^2 = 0 => perfect square
x = {-2}, or x = {-2, -2}