HELP PLEASE !
Use the function f(x)=-3(x+1)^2+18

Step-by-step explanation:

From the given function,

f(x) = -3(x + 1)²+ 18

By comparing this equation with the standard equation of the quadratic function,

f(x) = a(x - h)² + k

Here, (h, k) is the vertex.

Part A

Vertex of the given equation → (-1, 18)

Part B

y-intercept → For the value of y at x = 0

y = -3(0 + 1)² + 18

y = -3 + 18

y = 15

y - intercept → (0, 15)

Part C

Since, the given function is opening downwards,

Function will have a maximum.

Part D

Coordinates of maximum point → (-1, 18)

Part E

Axis of symmetry → x = -1

answer: hence, function will be

explanation:

since we have given that

cost of a new textbook = $85

according to question, the resale value of a textbook decreases by 25% with each previous owner,

so, our function becomes,

here, y is the total value of the text book after x owners.

hence, function will be