Parameter Challenge: Find the Representation for a=-3, b=4, c=-15

To solve this problem, we need to construct the quadratic equation using the given parameters:

• Step 1: Identify the parameters from the problem statement:
  - $a = -3$, $b = 4$, $c = -15$.
• Step 2: Apply these parameters to the standard form of a quadratic equation:
  - The standard form is $y = ax^2 + bx + c$.
• Step 3: Substitute the given values into the standard form:
  - Substitute $a = -3$, $b = 4$, $c = -15$ into $y = ax^2 + bx + c$.

By substitution, the equation becomes:

$y = -3x^2 + 4x - 15$.

This expression correctly represents the quadratic equation using the specified parameters.

Therefore, the correct answer is option 3: $-3x^2 + 4x - 15$.