18 divided by 30 is 0.6. So I would say that B, or 0.6, is the correct answer.

Putting the value of Y = 15

So, X = 200
It is approximately -.4048
H=10^(-pH)
log H = -pH
pH=-logH => so it is affirmed that it is -.40
Answer:
x = 15
Step-by-step explanation:
-x = -15
x = -1 × (-15)
<u>x</u><u> </u><u>=</u><u> </u><u>1</u><u>5</u>
Completing the square follows the principle of taking

and converting it into

where d is the 'correctional number' as I like to call it - i.e. the number that converts the expanded bracket into the +c, since the expanded bracket will give us

.
In this case, 2/2=1 so we have the first part:

.
Expanding this gives us

. We need c to be 9, so we can just add 8.
Putting this together:

Now we can solve it more easily.
Rearranging: