Question

Let ​ x2+11x=3 ​.

Answer 1

Add (11/2)^2 to both sides
x^2 + 11x + (11/2)^2 = 3 + (11/2)^2
x^2 + 11x + (11/2)^2 = 133/4
(x + 11/2)^2 = 133/4
x + 11/2 = sqrt of (133/4)
Solutions are
x = (sqrt of (133) - 11))/2
x = (-sqrt of (133) -11))/2

Answer 2

X2+11x+(-3)=0

First bracket (-3), second bracket (0)

Hope this helps.