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Activity

Section 01 Complex Numbers

For exercises 1 to 4, write the number as a pure imaginary number in the form bi and simplify.

1.                      2.                        3.                    4. 

For exercises 5 to 10, perform the indicated operations and leave all i number answers in simplest terms.

5.          6.  2i x 3i                     7.  8i  - 15i                8.  i 11 x i 12     

9. i 6 + i 20                         10. 

11. Evaluate 2x3 - 4x2 + 6x - 3  for x =

For exercises 12 to 17  perform the indicated operations and express your answer in simplest terms.

12.  (10 - 6i) - (7 - 3i)                          13.  (4 + i ) - (3 + 2i) - (2 + 3i)

14.  2(5 + 3i) - (3 + i)(1 - i)                 15.  (5 + 2i)(1 - 3i)(2 + i)

16.  (1 - i)                                          17.               

18.  Evaluate   x2 + x + 1   for    x =

19.  Show that 3 + 2i  and 3 - 2i are roots of the equation   x2 - 6x = - 13 .

20.  Show that   and    are zeros of the function  f(x) = x2 - 4x + 9 .

Answers

Section 02 Polynomial Equations

Factor completely over the system of real numbers the polynomials in exercises 1 - 9 .

1.   32x3 - 48x2                           2.  3x2 - 27                                 3.  x4 - 16

4.  3x2 - 24x + 48                       5.  x2 - 9x + 18                           6. 2n2 - n - 3

7.  3n2 + 2nr - 3n - 2nr                8.  9x2 + 26x + 16                      9.  4x2 - 7

Find all roots, real or imaginary, of the equations in exercises 10 - 19

10.  3x2 = 5x                                       11.   x2 - 3x = 40

12.  2x3 - 238x = 0                              13.   5x2 - 14x - 3 = 0

14.  (x + 6)(x - 4) = 24                        15.   (x + 4)2 = 19(x + 4)

16.  x3 + 5x2 - x - 5 = 0                       17.   51x2 + x - 92 = 0

18.  x4 - 41x2 + 400 = 0                      19. 

20.  Find the quotient and remainder on dividing 2x3 - 3x2 + 5x - 7 by x - 2. Then express 2x3 - 3x2 + 5x - 7 as (x - 2)(Quotient) + Remainder.

21.  One of the factors of 6x3 + 13x2 - 4  is x + 2 . Find the other factors.

Find the rational roots of the  polynomial equations in exercises 22 - 24 (Hint: Use the rational roots theorem).

22. x3 - 4x2 + x + 6 = 0                        23.  2x3 - 5x2 - 14x + 8 = 0                24. 12x3 + x2 - 10x - 3 = 0

Answers

Section 03 Graphs

Use your knowledge of the "basic shape" and the relation between the real zeros and the x-intercepts to sketch the graph of each of the following functions. Do not use graphing technology other than as a check of your work.

1.   f(x) = 2                                                       2.   f(x) = - ( x + )

3.   f(x) = (x - 1)                                            4.   f(x) = - (x - 3)(x + 2)

5.    f(x) = (x + )( x - )                                6.   f(x) = x2 - 3x - 4

7.    f(x) = -(x + )(x - 1)(x - 3)                        8.   f(x) = x3 + x2 - 9x - 9

9.   f(x) = (x + 3)2(x - 1)(x + 2)                        10.   f(x) = - x4 + 26x2 - 25

Find the function for each of the graphs shown below:

11.      12.  

13.       14. 

15.      16.  

Answers

Section 04 Radical Equations

Solve each of the following equations:

1.                                        2.          

3.                                      4.      

5.                                      6. 

7.                               8. 

Answers

Test Yourself

1. Given the polynomial 3x2 - 4x3 + 2x - x4 + 5 
    (a) What type of polynomial is it?
    (b) What is the degree?
    (c) What is the leading coefficient?

2. Simplify:

   (a)  i 15i 17      (b) (2 + 5i) + (9 - 3i) - (6 - 2i)     (c)  (3 - i )(2 + 3i )

3. Verify that   is a zero of the function f(x) = 3x2 - 4x + 2 .

4. Find all the real roots of each of the following equations:

   (a)                                 (b)  4x2 + 12x + 9 = 0

   (c)  8x2 - 22x + 15 = 0                         (d)  36x4 - 25x2 + 4 = 0

   (e)  x3 + 4x2 - 9x - 36 = 0                    (f) 

   (g)                          (h)  10x3 - 17x2 - 7x + 2 = 0

5. What is the remainder when 2x15 - 3x8 + 2x2 - 5 is divided by x + 1 ?

6.  Sketch the graph of each of the following:

    (a) f(x) = x(x + 3)(x - 2)                              (b) f(x) = -(x - 3)(x - 4)(x + 2)2

7. Find the function that describes each of the following graphs:

   (a)     (b) 

Answers