Answer:
x is either 77 or -47
Step-by-step explanation:
For the given quadratic equation we only have a maximum at y = 18.
<h3>
How to find the extrema of the given function?</h3>
Here we have:

Notice that this is a quadratic equation of negative leading coefficient.
Then we have a maximum at the vertex, and both arms tend to negative infinity as x tends to infinity or negative infinity.
The vertex is at:
x = -(-4)/(2*(-2)) = -1
The maximum is:

If you want to learn more about quadratic equations:
brainly.com/question/1214333
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Step-by-step explanation:
I'll help you darling
a. B
b. 2.6 + x = 10.4
c. x = 10.4 - 2.6
= 7.8
d. This is to say before mia added the 2.6 litres of what the pitcher contained 7.8 litres of water already
Answer: 88.2
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