Q. f(x)=(2x−1)(3x+5)(x+1) has zeros at x=−35,x=−1, and x=21.What is the sign of f on the interval −35<x<21 ?Choose 1 answer:(A) f is always positive on the interval.(B) f is always negative on the interval.(C) f is sometimes positive and sometimes negative on the interval.
Determine Sign of f(x): Since f(x) is a product of three linear factors, we can determine the sign of f(x) by looking at the signs of each factor in the given interval.
Factor (2x−1): First, let's look at the factor (2x−1). For x values between −35 and 21, this factor is negative because 2x is always less than 1 in this interval.
Factor (3x+5): Next, the factor (3x+5) is positive for all x values in the interval, since 3x is always greater than −5 when x is greater than −35.
Factor (x+1): Lastly, the factor (x+1) is also positive for all x values in the interval, because x is always greater than −1.
Final Sign of f(x): Multiplying a negative by two positives gives a negative, so f(x) is negative for all x in the interval -\frac{5}{3} < x < \frac{1}{2}.