A parabola has a vertex at (-1,0) and opens down. What is the equation of the parabola?

y = -(x + 1)^2

Step-by-step explanation:

I graphed the parabola on the graph below so you can see that it has a vertex at (-1,0) and opens down.

step-by-step explanation:

assume that you have 3 different side lengths.   apply the pythagorean theorem here:   square each of the two shortest sides; call them a and b, so that their squares are a² and b².   also square the longest side, calling the result c².

now, if a² + b² = c² is true, the triangle is a right triangle; otherwise it is not a right triangle.