Inactive Tutor answered • 03/28/15
Tutor
New to Wyzant
f(v) = √(-3x + 21)
The number under the square-root cannot be negative, since there is no number when squared will result in a negative value.
-3x + 21 ≥ 0
-3x ≥ -21
x ≥ 7
Flip the inequality sign when dividing by a negative number.
x ≤ 7
The domain is (∞, 7].
