Y=(x+9)(x-3)+c
∵(-3,-36)lies on it.
-36=(-3+9)(-3-3)+c
-36=(-6)(-6)+c
-36=36+c
c=-36-36=-72
y=(x-9)(x+3)-72
y=x^2+3x-9x-27-72
y=x^2-6x-99
Using it's vertex, the maximum value of the quadratic function is -3.19.
<h3>What is the vertex of a quadratic equation?</h3>
A quadratic equation is modeled by:

The vertex is given by:

In which:
Considering the coefficient a, we have that:
- If a < 0, the vertex is a maximum point.
- If a > 0, the vertex is a minimum point.
In this problem, the equation is:
y + 4 = -x² + 1.8x
In standard format:
y = -x² + 1.8x - 4.
The coefficients are a = -1 < 0, b = 1.8, c = -4, hence the maximum value is:

More can be learned about the vertex of a quadratic function at brainly.com/question/24737967
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Answer:
<h3>ᎪꪀsωꫀᏒ</h3>
x= 7
Step-by-step explanation:
2x=14
x= 14/2
x= 7
answer: it would be one solution, becasue the variables are different and the constants dont matter, since the variables are different
60 grades in 10 minutes
So 6 grades in 1 minutes
11:00 to 11:40=40 minutes
So 6×40=240 grades in 40 minutes