Answer:
y = -(x + 1)² + 4
Explanation:
y = -x² − 2x + 3
First, factor the leading coefficient from the first two terms.
y = -(x² + 2x) + 3
Complete the square.
y = -(x² + 2x + 1 − 1) + 3
Simplify and factor.
y = -(x² + 2x + 1) + 1 + 3
y = -(x + 1)² + 4