The equation given in the question is written below
- 3 + x^2 = - 19
x^2 = - 19 + 3
x^2 = - 16
x^2 = - (4)^2
Then
x = - 4
So we can see from the above deduction that x is equal to -4 and not +4. I hope the procedure is clear enough for you to understand. You can always use this method for solving problems of similar kind without requiring any help from outside. Only be careful about the calculation part of the problem given.