How to find minimum and maximum of this equation.

Using it's vertex, the maximum value of the quadratic function is -3.19.
A quadratic equation is modeled by:
[tex]y = ax^2 + bx + c[/tex]
The vertex is given by:
[tex](x_v, y_v)[/tex]
In which:
Considering the coefficient a, we have that:
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:
[tex]y_v = -\frac{1.8^2 - 4(-1)(-4)}{4(-1)} = -3.19[/tex]
More can be learned about the vertex of a quadratic function at https://brainly.com/question/24737967
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