Question

Evaluate the function at the indicated values. (If an answer is undefined, enter UNDEFINED.)

f(x) = x2 + 7x


f(0) = 0


Correct: Your answer is correct.


f(3) = 30


Correct: Your answer is correct.


f(−3) = −12


Correct: Your answer is correct.


f(a) = a


Incorrect: Your answer is incorrect.


f(−x) =


f



1


a



=

Answer 1

a) The function is equal to 0 when
`x = 0`.

b) The function is equal to 30 when
`x = 3`.

c) The function is equal to -12 when
`x = -3`.

d) The function is equal to
`a\cdot (a+7)` when
`x = a`.

e) The function is equal to
`x\cdot (x-7)` when
`x = -x`.

Explanation:

To this respect we must keep in mind that this exercise consists in evaluating given function at different values. Let
`f(x) = x^(2)+7\cdot x` the function to be evaluated:

a)
`x = 0`

`f(0) = 0^(2)+7\cdot (0)`

`f(0) = 0`

The function is equal to 0 when
`x = 0`.

b)
`x = 3`

`f(3) = 3^(2)+7\cdot (3)`

`f(3) = 30`

The function is equal to 30 when
`x = 3`.

c)
`x = -3`

`f(-3) = (-3)^(2)+7\cdot (-3)`

`f(-3) = -12`

The function is equal to -12 when
`x = -3`.

d)
`x = a`

`f(a) = a^(2)+7\cdot a`

`f(a) = a\cdot (a+7)`

The function is equal to
`a\cdot (a+7)` when
`x = a`.

e)
`x = -x`

`f(-x) = (-x)^(2)+7\cdot (-x)`

`f(-x) = x^(2) -7\cdot x`

`f(-x) = x\cdot (x-7)`

The function is equal to
`x\cdot (x-7)` when
`x = -x`.