Wednesday, 20 November 2013

Maths Club


18 comments:

  1. 2b. 2[3x-4]=4[x+3]
    For the first part you will need to times 2 by 3x.
    2 times 3x =6x
    Next you will need to times 2 by 4.
    2 times 4 = 8
    So, the first part of the equation equals;6x-8
    For the next part you will need to times 4 by x.
    4 times x = 4x
    Then you will need to times 4 by 3.
    4 times 3 =12
    So , this part of the equation equals 4x+12.
    Now you will need to put the two parts of the equation together.
    6x-8=4x+12
    You now need to see which side of the equation has the least amount of x.
    The part of the equation on the right-hand side has the least amount of x.
    Take 4x away from both sides.
    4x-4x=0
    6x-4x=2x
    The equation has now turned into 2x-8=12.
    Therefore x=2

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    Replies
    1. Mahliqa I am going to use this explanation in class and claim it as my own it is so good! You have really broken this complex equation into really easy and simple steps. Well done!

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  2. Question 3a
    3(x+2) + 5(x-1) = 25
    Step 1 : You first factorise it, turning it into 3x + 6 + 5x -5 = 25
    Step 2 : Simplify this to 8x + 1 = 25
    Step 3 : Solve it like any other equation ( nearly any other) : do the inverse, which is:
    25 - 1 = 24
    24/8 (/ means divided by) = 3
    x = 3.

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  3. Super! I really like your use of / for divide, it really annoys me that there isn't a division sign button on a standard keyboard!

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  4. 3a (which is 3(x+2)+5(x-1)=25)
    3 is the answer because 3+2=5
    5x3=15
    3-1=2
    2x5=10
    15+10=25
    then the equation makes sense and x equals 3

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  5. 2a) 2(3x+4) = 2( 4x-1) (multiply each number in the brackets by the number outside)

    6x+ 8 = 8x- 2
    8x- 2 = 6x+ 8 ( L.H.S = R.H.S or R.H.S = L.H.S)
    8x- 6x = 8+2 ( do the inverse)
    2x = 10 (simplify both sides)
    x = 10/2 (divide 10 by 2)
    x = 5

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  6. Question 1d: 11x + 5 = 9x + 21

    1. Before you calculate you need to separate the numbers with x from the numbers without x. If you move the number to the other side of the equals sign it becomes the opposite of what it was ( in this case 9x becomes -9x and 5 becomes -5).
    11x - 9x = 21 - 5

    Now you subtract.

    2. 2x = 16

    If you want to find the value of x you need to divide both sides by the number standing next to x.
    2x = 16 / 2

    The value of x is 8.

    3. To double check if your calculation is correct you can fill in the x with an answer.
    11 x 8 + 5 = 9 x 8 + 21
    Don't forget the multiplication is always before addition!
    93 = 93

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  7. 2e). 4(3x+2 = 10(x+4)

    First multiply out the brackets to give:

    12x+8 = 10x+40

    Then you start to collect like terms (CLT) on both sides of the equations:

    So, 2x+8 = 40
    2x = 40 - 8
    2x = 32
    x = 32 ÷ 2 = 16

    x = 16

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  8. are you allowed to do this even if your not in maths club?

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    Replies
    1. Of course Maanav, give it a go!

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    2. Ok I will give it a go.

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  9. Dear Mr Troy, I am Ishaan from Downing Street and I am in your Year 3 Maths Club. I am learning how to solve equations, and I have solved all the ones in this blog, but I am showing only Q.2a here.

    2(3x + 4) = 2(4x − 1)

    6x + 8 = 8x − 2

    6x − 8x = −2 − 8

    −2x = −10

    x = −10 ÷ −2

    x= 5

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    Replies
    1. This is absolutely fantastic Ishaan! We will clearly have to go through the rest of them in our afternoon sessions.

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  10. 1.
    (a)2x+4=3x+1
    x=3
    (b)10x+8=4x+38
    x=5
    2.
    (a) 2(3x+4)=2(4x-1)
    =6x+8=8x-2
    2x=10
    x=5





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