The third one.
Because the answer of the absulate value equations is always positive.
Answer:
Group the like terms
6x + 3x - x + 9
Work out the x values together and then add the 9
9x - x + 9
8x + 9
your final answer should be about 8x + 9 as it cannot be simplified anymore
Yeah, mostly is has to be negative, but in some cases a is greater than 1 than we do some other operations.
Answer:
(-1,-2)
Step-by-step explanation:
Let's bring back to memory vertex formula for parabolas.

Where (h,k) is the vertex.
In 
The vertex is (-1,-2)
Remark
This is an arithmetic progression. You have the first and last terms and the difference.
Givens
a = - 18
L = 60
d = 4.5
Equation
L = a + (n - 1)d
Solve
60 = -18 + (n - 1) * 4.5 Add 18 to both side
60 + 18 = (n - 1) * 4.5
78 = (n - 1) * 4.5 Divide both sides by 4.5
78/4.5 = n - 1
17.3333 = n - 1 Add 1 to both sides.
18.3333 = n
Conclusion
It will that 18 1/3 or 18.33333 minutes to get the from -18 to 60 degrees.