Grade 11 Polynomials & Rational Expressions Practice

Question 1 of 50Score 0/0Medium

Question 1 of 50: Use the Remainder Theorem: what is the remainder when x⁴ − 5x² + 4 is divided by (x + 2)?

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Answer key for parents & teachers (50 questions)
  1. Use the Remainder Theorem: what is the remainder when x⁴ − 5x² + 4 is divided by (x + 2)?0. p(−2) = 16 − 20 + 4 = 0. The remainder is 0, which means (x + 2) is a factor.
  2. According to the Rational Root Theorem, which are candidate rational roots of 2x³ − 3x + 1?±1, ±2, ±1/2. Rational Root Theorem: candidates are ±(factors of constant)/(factors of leading coeff) = ±(1)/(1, 2) = ±1, ±1/2.
  3. After synthetic division of p(x) by (x − c), the last number in the row is:The value of p(c). In synthetic division, the last number in the bottom row is the remainder, which equals p(c) by the Remainder Theorem.
  4. What is the remainder when p(x) = x³ − 3x² + 2x − 5 is divided by (x − 3)?−1. p(3) = 27 − 27 + 6 − 5 = 1. Wait: 27 − 27 = 0, 0 + 6 = 6, 6 − 5 = 1. The remainder is 1.
  5. How many steps does synthetic division of a degree-3 polynomial by a linear factor require?3. Synthetic division processes the coefficients one by one. For a degree-3 polynomial (4 coefficients), there are 3 multiply-and-add steps after bringing down the first.
  6. If p(x) = x³ + ax² + bx + c has (x − 2) and (x + 1) as factors, what is p(2) + p(−1)?0. If (x − 2) and (x + 1) are factors, then p(2) = 0 and p(−1) = 0. Therefore p(2) + p(−1) = 0 + 0 = 0.
  7. What is the result of dividing x³ − 1 by (x − 1)?x² + x + 1. x³ − 1 = (x − 1)(x² + x + 1). After division, the quotient is x² + x + 1 with remainder 0.
  8. Use synthetic division: divide 3x² − 5x + 2 by (x − 2). What is the remainder?0. p(2) = 3(4) − 5(2) + 2 = 12 − 10 + 2 = 4. Wait: 12 − 10 = 2, 2 + 2 = 4. Remainder = 4. Correction: p(2) = 4.
  9. What is a "depressed polynomial" after synthetic division?A polynomial with degree reduced by 1. After synthetic division of a degree-n polynomial by a linear factor, the quotient has degree n−1. This quotient is called the "depressed polynomial."
  10. The quotient when dividing a degree-5 polynomial by (x² + 1) has degree:3. When dividing a degree-5 polynomial by a degree-2 polynomial, the quotient has degree 5 − 2 = 3.
  11. Which scenario confirms (x + 4) is NOT a factor of p(x)?p(−4) ≠ 0. (x + 4) = (x − (−4)), so c = −4. If p(−4) ≠ 0, then by the Factor Theorem, (x + 4) is NOT a factor.
  12. What is p(1) for p(x) = xⁿ − 1 for any positive integer n?0. p(1) = 1ⁿ − 1 = 1 − 1 = 0 for any n. This confirms (x − 1) is always a factor of xⁿ − 1.
  13. What is the sum of cubes factorization formula for a³ + b³?(a + b)(a² − ab + b²). a³ + b³ = (a + b)(a² − ab + b²). Note the middle term of the trinomial is NEGATIVE for the sum of cubes.
  14. Factor: 8x³ − 1.(2x − 1)(4x² + 2x + 1). 8x³ − 1 = (2x)³ − 1³. Using difference of cubes: (2x − 1)((2x)² + (2x)(1) + 1²) = (2x − 1)(4x² + 2x + 1).
  15. Factor x³ + 8 completely.(x + 2)(x² − 2x + 4). x³ + 8 = x³ + 2³. Using sum of cubes a³ + b³ = (a+b)(a²−ab+b²): (x+2)(x²−2x+4).
  16. Factor x³ + x² − 4x − 4 using grouping.(x + 1)(x − 2)(x + 2). Group: x²(x+1) − 4(x+1) = (x²−4)(x+1) = (x−2)(x+2)(x+1).
  17. Factor 27x³ + 1 completely.(3x + 1)(9x² − 3x + 1). 27x³ + 1 = (3x)³ + 1³. Sum of cubes: (3x + 1)((3x)² − (3x)(1) + 1) = (3x + 1)(9x² − 3x + 1).
  18. Factor x³ − 3x² − x + 3 by grouping.(x − 3)(x + 1)(x − 1). Group: x²(x−3) − 1(x−3) = (x²−1)(x−3) = (x+1)(x−1)(x−3).
  19. What is the GCF of 6x³y + 9x²y² − 3x²y?3x²y. GCF of coefficients 6, 9, 3 is 3. GCF of x³, x², x² is x². GCF of y, y², y is y. So GCF = 3x²y.
  20. Factor 2x³ − 2x² − 12x completely.2x(x − 3)(x + 2). Factor GCF 2x first: 2x(x² − x − 6) = 2x(x − 3)(x + 2).
  21. Which of the following is the correct factored form of x³ − 8x² + 16x?x(x − 4)². Factor GCF x: x(x² − 8x + 16) = x(x − 4)². Check: (x−4)² = x²−8x+16. ✓
  22. How many real roots does x³ + 1 = 0 have?1. x³ + 1 = (x+1)(x²−x+1) = 0. x = −1 is a real root. The quadratic x²−x+1 has discriminant 1−4=−3<0, giving 2 complex roots. Total real roots: 1.
  23. Factor: 5x⁴ − 20x².5x²(x − 2)(x + 2). GCF = 5x². Then 5x²(x² − 4) = 5x²(x − 2)(x + 2). Factor completely using difference of squares.
  24. If p(x) = (x − 1)²(x + 3), how many distinct roots does p(x) have?2. Distinct roots: x = 1 (from (x−1)², a double root) and x = −3. There are 2 distinct real roots.
  25. The polynomial x² + 4 (over the reals):Is irreducible over the reals. x² + 4 has no real factors because x² + 4 > 0 for all real x (no real roots). It is irreducible over ℝ. Over ℂ it factors as (x+2i)(x−2i).
  26. After factoring by grouping 2x³ − x² + 6x − 3, what is the complete factorization?(x² + 3)(2x − 1). Group: x²(2x−1) + 3(2x−1) = (x²+3)(2x−1).
  27. For f(x) = (x² + 2x)/(x + 2), is there a hole?Yes, there is a hole at x = −2. Factor numerator: x(x+2). The (x+2) cancels with the denominator → hole at x = −2.
  28. What is the domain of f(x) = (x − 1)/(x² + x − 6)?All reals except x = 2 and x = −3. x² + x − 6 = (x+3)(x−2). Domain excludes where denominator = 0: x = 2 and x = −3.
  29. Which rational function has a hole at x = 1 and a vertical asymptote at x = −2?(x−1)/[(x+2)(x−1)]. (x−1)/[(x+2)(x−1)]: the (x−1) cancels → hole at x=1. Remaining denominator (x+2) → vertical asymptote at x=−2.
  30. If deg(numerator) = deg(denominator) + 1, the graph of the rational function has:An oblique (slant) asymptote. When the degree of the numerator is exactly 1 more than the denominator, polynomial long division yields a linear quotient, giving an oblique (slant) asymptote.
  31. What is the y-intercept of f(x) = (2x + 6)/(x² − 9)?y = −2/3. y-intercept: f(0) = (0+6)/(0−9) = 6/(−9) = −2/3.
  32. f(x) = (x² − 1)/(x − 1) is equivalent to which function (with a restriction)?f(x) = x + 1, x ≠ 1. (x²−1)/(x−1) = (x+1)(x−1)/(x−1) = x+1, but only when x ≠ 1 (since the original is undefined there).
  33. How many vertical asymptotes does f(x) = (x² + 1)/(x² − 5x + 6) have?2. Factor denominator: (x−2)(x−3). Numerator x²+1 is never zero. Neither factor cancels. So there are 2 vertical asymptotes: x = 2 and x = 3.
  34. A rational function f(x) has a horizontal asymptote at y = 0. What does this tell us about end behavior?f(x) → 0 as x → ±∞. A horizontal asymptote y = 0 means that as x → +∞ or x → −∞, f(x) approaches 0 (the x-axis is an asymptote for the end behavior).
  35. What is the behavior of f(x) = 1/x as x approaches 0 from the right (x → 0⁺)?f(x) → +∞. As x → 0⁺ (small positive values), 1/x becomes very large positive. So f(x) → +∞.
  36. For f(x) = (2x − 6)/(x² − 9), where is the hole?x = 3. Factor: numerator = 2(x−3), denominator = (x+3)(x−3). The (x−3) cancels → hole at x = 3. Remaining asymptote: x = −3.
  37. A rational function has no x-intercepts. What does this mean?The numerator is never zero. x-intercepts occur where the numerator equals zero (and denominator is nonzero). If the numerator is never zero (e.g., x²+1), there are no x-intercepts.
  38. Does f(x) = (x + 1)/(x² + 1) have any vertical asymptotes?No, x² + 1 > 0 for all real x. x² + 1 > 0 for all real numbers (minimum value is 1 at x = 0). So the denominator is never zero, and there are no vertical asymptotes.
  39. What is the domain restriction when simplifying (x² − 4)/(x − 2)?x ≠ 2 only. The original expression is undefined when x − 2 = 0, so x ≠ 2. Even after simplifying to x + 2, the restriction x ≠ 2 remains.
  40. Simplify: [(x²−1)/(x+2)] · [(x+2)/(x+1)]x − 1. [(x+1)(x−1)/(x+2)] · [(x+2)/(x+1)]. Cancel (x+2) and (x+1): result = x − 1.
  41. Add: (2/x) + (3/(x+1)). What is the result?(2x+5)/(x(x+1)). LCD = x(x+1). 2(x+1)/(x(x+1)) + 3x/(x(x+1)) = (2x+2+3x)/(x(x+1)) = (5x+2)/(x(x+1)).
  42. Simplify: (x² + 5x + 6)/(x² + 4x + 4).(x+3)/(x+2). Factor: numerator = (x+2)(x+3), denominator = (x+2)². Cancel one (x+2): (x+3)/(x+2). (x ≠ −2)
  43. Perform: [(x−1)/(x+3)] ÷ [(x²−1)/(x+3)].1/(x+1). Flip second fraction: [(x−1)/(x+3)] · [(x+3)/(x²−1)] = (x−1)/(x²−1) = (x−1)/[(x−1)(x+1)] = 1/(x+1).
  44. What is the excluded value in the expression (x+4)/[(x−2)(x+4)]?x = 2 and x = −4. The expression is undefined when either (x−2) = 0 or (x+4) = 0, giving x = 2 or x = −4. Even though (x+4) cancels when simplifying, x = −4 is still excluded.
  45. Subtract: (3/(x+1)) − (2/(x−1)). What is the numerator?x − 5. LCD = (x+1)(x−1). [3(x−1) − 2(x+1)] / [(x+1)(x−1)] = [3x−3−2x−2]/... = (x−5)/[(x+1)(x−1)].
  46. The form A/(x−a) + B/(x−b) is the partial fraction setup for which type of denominator?Distinct linear factors. When the denominator has two distinct linear factors (x−a)(x−b), the partial fraction decomposition uses A/(x−a) + B/(x−b).
  47. Simplify: [1/(x+2)] · [(x²−4)/(x−2)].1. Multiply: (x²−4)/[(x+2)(x−2)] = (x+2)(x−2)/[(x+2)(x−2)] = 1. (x ≠ ±2)
  48. Simplify: (x³ − 8)/(x − 2).x² + 2x + 4. x³ − 8 = (x−2)(x²+2x+4). Dividing by (x−2) gives x² + 2x + 4. (x ≠ 2)
  49. Solve: (x+1)/(x−3) = 2.x = 7. Cross multiply (or multiply both sides by (x−3)): x+1 = 2(x−3) = 2x−6. Then 1+6 = 2x−x → x = 7. Check: 8/4 = 2 ✓.
  50. What is an "extraneous solution" in rational equations?A solution that makes the denominator zero. An extraneous solution is a value that satisfies the transformed equation but makes the original expression undefined (denominator = 0). Always check solutions in the original equation.