Browse · harp
Printsmc
algebra senior
Problem
When the roots of the polynomial are removed from the number line, what remains is the union of disjoint open intervals. On how many of these intervals is positive?
(A)
(B)
(C)
(D)
Solution
The expressions to the power of even powers are always positive, so we don't need to care about those. We only need to care about . We need 0, 2, or 4 of the expressions to be negative. The 9 through 10 interval and 10 plus interval make all of the expressions positive. The 5 through 6 and 6 through 7 intervals make two of the expressions negative. The 1 through 2 and 2 through 3 intervals make four of the expressions negative. There are intervals.
Final answer
C