Constructing an Algebraic Expression with Constants: a = -1, b = -16, c = -64

To solve the problem, we will create an algebraic expression using the specified parameters.

• Step 1: Start with the general form of a quadratic expression: $y = ax^2 + bx + c$.
• Step 2: Substitute the given values ($a = -1$, $b = -16$, $c = -64$) into the form. This yields: $y = -1x^2 - 16x - 64$.
• Step 3: Simplify the expression. Since the terms are already simplified, the expression remains: $y = -x^2 - 16x - 64$.

Therefore, the algebraic expression based on the given parameters is $-x^2 - 16x - 64$.

Final solution: The correct answer is $-x^2 - 16x - 64$.

Among the given choices, this corresponds to choice 4:

$-x^2-16x-64$