Question

Find the function value, if possible. (If an answer is undefined, enter UNDEFINED.)

f(x) =

−5x − 5, x < −1
x2 + 2x − 1, x ≥ −1
(a)
f(−4)



(b)
f(−1)



(c)
f(1)

Answer 1

(a) 15

(b) -2

(c) 2

Explanation:

For each given value of x, determine the applicable function definition and use that to determine the function value.

(a)

-4 is less than -1, so the first function definition applies:

f(-4) = -5(-4) -5 = 20 -5

f(-4) = 15

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(b)

-1 is equal to -1, so the second function definition applies:

f(-1) = (-1)^2 +2(-1) -1 = 1 -2 -1

f(-1) = -2

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(c)

1 is greater than -1, so the second function definition applies:

f(1) = (1)^2 +2(1) -1 = 1 + 2 -1

f(1) = 2