2. which equation represents y=-x2 - 10x-20 in vertex form?
y=-(x+5)* + 10
y=-(x– 5)° +15
y=-(x - 5)*+5
y=-(x+5)* +5

Step-by-step explanation:

The vertex form of a quadratic equation y = ax² + bx + c :

y = a(x - h)² + k

(h, k) - vertex

We have the equation

Convert to the vertex form:

      use (a + b)² = a² - 2ab + b²

answer: a.   one is a factor of every whole number since every number is divisible by itself.