ACT Math · Polynomial and rational functions
One solution to x³ - 2x² - 5x + 6 = 0 is x = 1. What is the sum of the other two solutions?
One solution to is . What is the sum of the other two solutions?
Answer and explanation
Answer: F: 1
Since is a root, divide by to get , so the other roots are and . Their sum is , choice F. A faster check uses Vieta's formulas: the three roots sum to (the opposite of the coefficient), and . Choice G, , reverses the sign of the sum. Choice H, , is the difference rather than the sum. Choice J, , is the product of the two roots (and the constant term of the quotient), not their sum.
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