Tuesday, April 7, 2009

Expand and Factorize Qs

Expand:

3(4x + 2y)

(8x - 2y) (4x + 6y)

(10i + 7j) (2j - x)

(17 + 2x) (2x + 3y)

(8w + 4x) (10x - 2W)




Factorize:

x^2 + 6x + 8

30 + x^2 + 13x

y^2 + 6y - 16

8 - x^2 - 6x

z^2 + 1z -56

29 comments:

  1. Expand
    Q1..
    3(4x+2y)
    we`first`multiple`
    (3*4x)which`is`12x`then
    (3*2y)which`is`6y
    so`together..
    12x+6y

    Factorize
    Q1..
    x^2 + 6x + 8

    first`we`multiply`(1*8)
    then`find`factors`which`results:6
    (1*8)(-1*8)
    (2*4)(-2*4)
    we`use`(2*4)`because`2+4=6
    so
    (x+2)(x+4)`is`the`answer..
    rewrite:

    x^2+6x+8
    (x+2)(x+4)

    ReplyDelete
  2. solution 1
    3(4x + 2y)
    remove brackets by mulitplying the outside term by each term in the bracket.
    = 3*4x + 3*2y
    = 12x + 6y

    ReplyDelete
  3. solution 2
    30 + x^2 + 13x
    step 1 (rearrenge the formula)
    x^2 + 13x + 30 = 0
    step 2
    find two numbers that when they are mulitplied they give a product of 30 and when added they give the sum of 13
    nos. are 3 and 10
    x^2 + 13x + 30 = 0

    (x+4)(x+10)=0
    sol. are x = -3, -10

    ReplyDelete
  4. question 1
    3(4x+2y)
    when we expand ... you multiple the outer unit with the one in the brackets seperate
    so......
    3 X 4x = 12
    and
    3 X 2y = 6y
    therefore when we expand the equa. you'll get ....
    12x+6y

    ReplyDelete
  5. you should be able to do the rest by using this method....

    ReplyDelete
  6. (8x - 2y) (4x + 6y)
    =32x^2+48xy-8xy-12y^2
    =32x^2+40xy-12y^2

    ReplyDelete
  7. solution 1
    3(4x + 2y)
    remove brackets by mulitplying the outside term by each term in the bracket.
    = 3*4x + 3*2y
    = 12x + 6y

    ReplyDelete
  8. (8x - 2y) (4x + 6y)
    =32x^2+48xy-8xy-12y^2
    =32x^2+40xy-12y^2

    ReplyDelete
  9. solution 2
    30 + x^2 + 13x
    step 1
    x^2 + 13x + 30 = 0
    step 2
    find two numbers that when they are mulitplied they give a product
    nos. are 3 and 10
    x^2 + 13x + 30 = 0

    (x+4)(x+10)=0
    sol. are x = -3, -10

    ReplyDelete
  10. 3(4x + 2y)

    expanding the equation you get

    12x + 6y

    all you need to remember is that you mulitlpy what in outside the bracket by each term inside the bracket.

    ReplyDelete
  11. (8x - 2y) (4x + 6y)

    I would take this approach

    8x (4x + 6y) -2y (4x + 6y)

    32x^2 + 48xy -8 xy -12y^2

    grouping together like terms
    32 x^2 + 40xy - 12 y^2

    ReplyDelete
  12. (10i + 7j) (2j - x)

    so using the same approach as the question before

    10i (2j -x) 7j ( 2j-x)

    20ij -10ix + 14j^2 -7jx

    ReplyDelete
  13. (17 + 2x) (2x + 3y)

    17 (2x+ 3y) 2x (2x + 3y)

    34x + 51y + 4x^2 + 6xy

    from this point you can factorise out x and y

    ReplyDelete
  14. (8w + 4x) (10x - 2W)

    8w (10x -2w) 4x ( 10x - 2w)
    80 wx -16 w^2 + 40 x^2 -8 xw

    grouping like term

    72 wx - 16w^2 + 40 x^2

    ReplyDelete
  15. x^2 + 6x + 8

    factorising

    we say factors of 8 beacuse we multiplty term a * c which will give a result of the term b

    using 4 and 2

    x ^2 + 4 + 2 + 8

    (x + 4) (x + 2)

    ReplyDelete
  16. 3(4x + 2y)

    multiple everything in the brackets by 3

    12x + 6y

    ReplyDelete
  17. (8x - 2y) (4x + 6y)

    we multiple each term in the first bracket by each term in the second bracket.

    32x^2 + 48xy - 8xy - 12y^2

    ReplyDelete
  18. (10i + 7j) (2j - x)

    we multiple each term in the first bracket by each term in the second bracket.

    20ij - 10ix + 14j^2 -7jx

    ReplyDelete
  19. (17 + 2x) (2x + 3y)

    34x + 51y + 4x^2 +6xy

    note: this question an a few about, can be further simplified in to a smaller term, but the question asked to expand the bracket terms, so i left it without simplifying

    ReplyDelete
  20. (8w + 4x) (10x - 2W)

    80wx - 16wW + 40x^2 - 8Wx

    note the different font size of the letter w, it is taken as different terms

    ReplyDelete
  21. Expand:
    3(4x+2y)

    First you multiply the number,outside of () by the first term/variable
    3*4x= (3*4) is 12, since there's 4x
    the answer is 12x.

    Next, multiply the number by the 2nd term/variable
    3*2y= (3*2) is 6, since there's 2y
    the answer is 6y

    Now considering the sign between both terms is +, you combine the two results.

    12x + 6y.

    ReplyDelete
  22. (8x-2y)(4x+6y)

    First you take it term by term.
    1st. 8x*4x

    2nd. 8x*6y

    3rd. -2y*4x

    4th. -2y*6y

    *there is a step by step process,
    where you

    NOTE:
    WHEN THERE IS TWO VARIABLES IN TWO BRACKETS, YOU HANDLE THEM SINGLE HANDEDLY.

    -MULTIPTY the 1st term by the 3rd term.
    -MULTIPLY the 1st term by the 4th term.

    -MULTIPLY the 2nd term by the 3rd term.
    -MULTIPLY the 2nd term by the 4th term.

    Gather like terms together.
    32x^2 + 48xy - 8xy - 12y^2

    Calculate the result when like terms have been combined.
    32x^2 + 40xy - 12y^2

    ReplyDelete
  23. Questions:
    1. (7x-3y)(12y+2x)
    2. (8m+3t)(4m-7z)
    3. (4q+12b)(2k+2b)
    4. (10p-20m)(40p-3m)

    ReplyDelete
  24. This comment has been removed by the author.

    ReplyDelete
  25. Answers: (10i+7j)(2j-x)

    1st. 10i * 2j= 20ij
    2nd. 10i * -1x= -10ix
    3rd. 7j * 2j= 14j^2
    4th. 7j * -1x= -7jx

    Writeout:
    20ij -10ix +14j^2 -7jx

    Re-write:
    14j^2 + 20ij -10ix -7jx

    ReplyDelete
  26. Answer: (17+2x)(2x+3y)

    1st. 17 * 2x= 34x
    2nd. 17 * 3y= 51y
    3rd. 2x * 2x= 4x^2
    4th. 2x * 3y= 6xy

    Writeout:
    34x + 51y + 4x^2 + 6xy

    Re-write:
    4x^2 + 34x + 51y + 6xy

    ReplyDelete
  27. Answer:
    Using as a 1st example...

    Steps u can use:
    1st. Multiply (a)*(c)= value

    2nd. Find factors of the value, that when computed with the two multiples, would give (b).

    3rd. Group terms together.

    4th. Organize the terms in order.

    5th. Solve.

    a b c
    Factorize:- x^2 + 6x + 8

    1st. The co-efficient of x is 1.
    So, 1*8 =8

    2nd. 1*8=8
    2*4=8
    You want to find, positive (+) 6x
    1*8=8
    but; 1+8=9 & 8-1=7 Not 6
    So try, 2*4=8 and 2+4=6 & 4+2=6 .Use this.

    x^2 + 2x + 4x + 8

    Note: there are common things in the 1st and 2nd terms & things are in the 3rd and 4th as well.

    x(x + 2) 4(x + 2)

    (x + 2) is common to both.

    Note: Depending on the sign of the other two terms outside, those in brackets would determine how it is written when organized into brackets.

    Here, it is positive (+) x and positive (+) 4. Therefore, it is (x + 4)

    We now derive at the answer...

    (x + 2) (x + 4).

    ReplyDelete
  28. Answer 30 + x^2 + 13x

    First reorganize into: x^2 + 13x + 30
    Then follow the steps as I've laidout above.

    The co-efficient of x^2 is 1.

    a * c
    1 * 30=30

    Required to find 13x.

    1 * 30=30
    2 * 15=30......... -2 + 15=13.... I'll use.
    15 - 2=13

    x^2 -2x + 15x + 30

    x(x - 2) 15(x - 2)

    Answer: (x + 15) (x - 2)

    ReplyDelete
  29. Q.1
    3(4x+2y)
    =3*4x=12x and
    3*2y=6y
    ans =12x+6y

    ReplyDelete