Question

What are the domain and range of the function f(x)=x^2-2x-4?
domain: all real numbers
range: all real numbers greater than or equal to –5
domain: all real numbers
range: all real numbers greater than or equal to –4
domain: all real numbers between –2.5 and 2.5
range: all real numbers
domain: all real numbers between –2.5 and 2.5
range: all real numbers greater than or equal to –5

Answer 1

Correct choice:
domain: all real numbers
range: all real numbers greater than or equal to −5

Reason: f(x)=x^2−2x−4 is a parabola opening upward. Its vertex is at x = 1 with value f(1) = −5, so the minimum is −5 and y ≥ −5.