Question

I ONLY HAVE 3 MINUTES LEFT HELP!

1. What is the range of f(x) = -x^2 + 4, if the domain is {2,0,1}?

A) {0,3,5}

B) {0,4,3}

C) {0,4,5}

D) {8,4,3}

2.

What is the domain of the quadratic function given by f(x) = 2x^2 + 2x - 4?

A) [0, +[infinity])

B) all real numbers

C) all negative real numbers

D) all positive real numbers

3. The barber’s profit each week depends on his charge c per haircut. It is modeled by p = -200c^2+ 2400c – 4700. What is the reasonable domain of this function, given this situation?

A) c ≥ 0

B) all real numbers

C) 0 ≤ c ≤ 2. 5

D) 2. 5 ≤ c ≤ 9. 5

Answer 1

Answer: 1: C, 2: B, 3: D

Explanation:

1.

`f(x) = -x^(2) + 4`

put x = 2

f(2)= 0

put x = 0

f(0) = 4

put x = 1

f(1) = 3

2.

f(x) = 2x^2 + 2x - 4

(you can use middle-term break or quadratic formula here but I used middle-term break).

2
`x^(2)` +4x -2x -4

2x(x + 2) -2(x + 2)

(x + 2) (2x -2)

x = -2, x = 1

all real numbers

3.

use quadratic formula

`c = \frac{-b +-\sqrt{b^(2) -4ac} }{2a}`

c = 9.5 and c = 2.5