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f(x)=(x-1)(4x+3)(3x-8) has zeros at 
x=-(3)/(4),x=1, and 
x=(8)/(3).
What is the sign of 
f on the interval 
-(3)/(4) < x < 1 ?
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.

f(x)=(x1)(4x+3)(3x8) f(x)=(x-1)(4 x+3)(3 x-8) has zeros at x=34,x=1 x=-\frac{3}{4}, x=1 , and x=83 x=\frac{8}{3} .\newlineWhat is the sign of f f on the interval 34<x<1 -\frac{3}{4}<x<1 ?\newlineChoose 11 answer:\newline(A) f f is always positive on the interval.\newline(B) f f is always negative on the interval.\newline(C) f f is sometimes positive and sometimes negative on the interval.

Full solution

Q. f(x)=(x1)(4x+3)(3x8) f(x)=(x-1)(4 x+3)(3 x-8) has zeros at x=34,x=1 x=-\frac{3}{4}, x=1 , and x=83 x=\frac{8}{3} .\newlineWhat is the sign of f f on the interval 34<x<1 -\frac{3}{4}<x<1 ?\newlineChoose 11 answer:\newline(A) f f is always positive on the interval.\newline(B) f f is always negative on the interval.\newline(C) f f is sometimes positive and sometimes negative on the interval.
  1. Check signs interval: Check the signs of each factor in the interval 34<x<1-\frac{3}{4} < x < 1.
  2. Analyze x1x-1: For x1x-1, when xx is between 34-\frac{3}{4} and 11, x1x-1 is negative because 11 is greater than any number in that interval.
  3. Analyze 4x+34x+3: For 4x+34x+3, when xx is 34-\frac{3}{4}, 4x+34x+3 equals 00. If xx is greater than 34-\frac{3}{4} but less than 11, 4x+34x+3 is positive because 4x+34x+300 times any number greater than 34-\frac{3}{4} plus 4x+34x+322 is positive.
  4. Analyze 3x83x-8: For 3x83x-8, when xx is between 34-\frac{3}{4} and 11, 3x83x-8 is negative because 33 times any number less than 83\frac{8}{3} minus 88 is negative.
  5. Multiply signs: Now, multiply the signs of each factor. Negative (from x1x-1) times positive (from 4x+34x+3) times negative (from 3x83x-8) gives a positive result.
  6. Final result: Since the product of the signs of the factors is positive, ff is always positive on the interval 34<x<1-\frac{3}{4} < x < 1.

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