Respuesta:
36
Explicación paso a paso:
Para completar el cuadrado tendremos que sumar la mitad del cuadrado del coeficiente de x a la expresión;
Coeficiente de x = -12
Mitad del coeficiente = (-12/2) = -6
Tomando el cuadrado del resultado = (-6) ^ 2 = 36
Por lo tanto, el número que se debe sumar para obtener un cuadrado perfecto es 36.
Answer: 
Explanation:
Follow PEMDAS in reverse to undo what's happening to x.
We first add 1 to both sides, then divide both sides by 5 to fully isolate x.
Refer to the steps below to see what I mean.

The inequality sign stays the same the entire time. The only time it flips is when you divide both sides by a negative number.
The solution set for x is anything -3 or larger.
If x was an integer, then we could say the solution set is {-3, -2, -1, 0, 1, 2, 3, 4, 5, 6, ...}
The correct answer is 3 hours. Hope this helps! ^_^
C would be the correct answer
A would mean that 6=3*18, which is incorrect
B would mean that 3=6*18 which is also incorrect
C would mean that 18=6*3 which is CORRECT
D would mean that 18=6*2 which is also incorrect
Therefore, C would be the correct answer