15) Solve.
15) An endangered species of fish has a population that is decreasing exponentially
(A = Apekt). The population 9 years ago was 1700. Today, only 1000 of the fish are alive.
Once the population drops below 100, the situation will be irreversible. When will this
happen, according to the model? (Round to the nearest whole year.)

let's cover over the formula of the vertex:

y = a(x – h)^2 + k

in this formula, (h,k) are the vertex, always remember that the positive or negative value of the vertex is based on the sign it has.

for example, if the vertex is -3,-6 then both the x and y value would have the positive sign attached to it and if it were a positive x and y value, then a negative sign would be attached to it.

with that being said, for our problem the x value is a positive one so we are looking for a number with a negative sign next to it, in this case the first and second choice.

however, for the first answer choice it isn't quite part of the formula so we know that the answer choice correctly displays the x value.

to confirm, we can see if the -1 fits correctly with the second answer choice, and as mentioned above a negative number will have a positive sign attached to it. so, for our problem we can see that -1 has been changed to +1, so we can confirm that the second answer choice is correct.

hence, our final answer is y=(x - 1)^2 + 1

correct choice is a

step-by-step explanation:

the equation of the line passing through the points and is

thus, the equation of the line that passes through the points (0, -6) and (-3, 0) is