Question 621223
22. Which are upper and lower bounds for the real roots of 3x4 − 2x3 + x − 9 = 0? 
A. 0 and 3 
B. –2 and 2 
D. –3 and –1, 1, and 3
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Using rational roots theorem

...0...|....3........-2.........0........1........-9.....
...1...|....3.........1.........1.........2........-7........
...2...|....3.........4.........8.........17.......25.... (2 is upper bound, all numbers>0)
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...0...|....3........-2.........0.........1.........-9.....
.-1...|....3........-5.........5.......-4.........-5.....
.-2...|....3........-8........16......-31........53....(-2 is lower bound, numbers alternate in sign)
ans: B. -2 and 2