Question 143961
(x + 3)^2 = 28

expand LEFT

x^2+6x+9=28

shift RIGHT to LEFT

x^2+6x-19=0

USE QUADRATIC FORMULA

*[invoke quadratic "x", 1, 6, -19 ]

Additionally,
(x + 3)^2 = 28
x+3=+/- sqrt(28)
x=-3+/-sqrt(28)
x=-3+/- 2sqrt(7)