Step-by-step explanation:
An a quadratic equation,
[tex] {ax}^{2} + bx + c = 0[/tex]
If the quadratic has one solution,
then
[tex]b {}^{2} - 4ac = 0[/tex]
So plug in 27 for c, and 3 for a
[tex] {b}^{2} - 4(3)(27) = 0[/tex]
[tex] {b}^{2} - 324 = 0[/tex]
[tex] {b}^{2} = 324[/tex]
[tex]b = 18[/tex]
or
[tex]b = - 18[/tex]
So our answer is 18 or -18