Jack threw a rock into the lake and is represented by the equation f(x)=-3x^2-6x+21, where f(x) is the height in feet and x, is the time in seconds. find the h, of the vertex (h, k) and find the zeros. what does each mean in the context of the question?

5.6%

step-by-step explanation:

answer: i realy don't get it that much can you me figer it out pleas you

step-by-step explanation:

7.25

step-by-step explanation:

we know that 7 equals to 7.0. we also know that 1/4=0.25. so we can add the two together and we get 7.25

i can answer this if i have the answer choices