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This practice test provides a comprehensive review of methods to find rational zeros and determine factors of polynomial functions. It covers various examples, including cubic and higher-degree polynomials, with step-by-step synthetic division and analysis of complex zeros. Students are encouraged to identify all possible rational zeros and verify if binomials are factors of given polynomials. Key exercises include exploring the relationships between coefficients and roots, applying the Rational Root Theorem, and simplifying polynomial equations.
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Unit 3 Practice Test Review
5x4– 31x3+ 11x2 – 31x + 6 p 1, 2, 3, 6 q 1, 5 p 1, 2, 3, 6, 1/5, 2/5, 3/5, 6/5 q Page 9 (back) 5) List all possible rational zeros of this polynomial:
-2x3 + 5x2 + 6x + 18 p 1, 2, 3, 6, 9, 18 q 1, 2 p 1, 2, 3, 6, 9, 18, 1/2, 3/2,9/2 q Page 9 (front) 4) List all possible rational zeros of this polynomial:
Page 9 back2) Determine if the binomial is a factor of the polynomial P(x) = x3 + 5x2 +7x + 9; x + 1 -1 1 5 7 9 -1 - 4 - 3 1 4 3 6 No when synthetically dividing with -1, the remainder is 6 not 0; so x + 1 is not a factor.
Page 9 (back) 4) x3 + x2 – x+ 15 = 0; is 1 – 2i is a zero? 1 – 2i| 1 1 -1 15 1 – 2i 1 2 – 2i (1 – 2i )(2 – 2i ) 2 – 2i – 4i + 4i 2 -2 – 6i 1 – 2i| 1 1 -1 15 1 – 2i -2 – 6i -15 1 2 – 2i -3 – 6i 0 Yes, when synthetically dividing with 1 – 2i, the remainder is zero; so 1 – 2i is a zero.
Page 9 (back) 9) If -1/3 is a zero of h(x) = 3x3 – 2x2 – 61x – 20 , find the other zeros. 3x3 – 2x2 – 61x – 20 -1/3 | 3 -2 -61 -20 -1 1 20 3 -3 -60 0 3x2 – 3x – 60 = 0 3(x2 – x – 20) = 0 3(x – 5)(x + 4) x = 5, -4
Page 9 (front) 9) x4 + 2x3 – 4x–4; -1 + i is a zero -1 + i| 1 2 0 -4 -4 -1 + i 1 1 +i (-1 + i )(1 + i ) -1 – i + i + i2 -2 -1 + i| 1 2 0 -4 -4 -1 + i -2 2 – 2i 4 1 1 +I -2 -2 – 2i 0 (-1 + i )(-2 – 2i) -2 + 2 i - 2 i - 2 i2 -1 - i| 1 1 + i -2 -2 – 2i 0 -1 – i 0 2 + i 1 0 -2 0 x 2 – 2 = 0 x = ±2
x4– x3– 10x2 + 4x + 24 -2 | 1 -1 -10 4 24 ↓ -2 6 8 -24 1 -3 -4 12 0 x3 – 3 x2 – 4x + 12 = 0 x2 ( x – 3 ) – 4 (x – 3 ) ( x – 3 ) (x2 – 4 ) (x – 3 ) ( x – 2 ) ( x + 2) y 5 x -5 -5 5 Page 9 (front) 7) Find all zeros
Page 9 (back) Find all zeros5x4 – 31x3 + 11x2 – 31x + 6 6 5 -31 11 -31 6 30 -6 30 -6 1/55 -1 5 -1 0 1 0 1 5 0 5 0 5x2 + 5 = 0 5(x2 + 1) = 0 x2 = -1 x = ± i x = 6, 1/5, ± i5(x + i)(x – i)(x – 6)(x – 1/5)
Page 9 (front) 8) Find all zeros 18x3 + 3x2 – 7x – 2 p 1, 2 q 1, 2 , 3, 6, 9, 18 p 1, 2, ½, 1/3, 2/3, 1/6, q 1/9, 2/9, 1/18 18x3 + 3x2 – 7x – 2 -½ | 18 3 -7 -2 ↓ -9 3 2 18 -6 -4 0 18x2 – 6x – 4 = 0 2(9x2 – 3x – 2) = 0 2(3x + 1)(3x – 2) x = -1/2, -1/3, 2/3 2(3x + 1)(3x – 2)(x + ½)