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    Simplify fully (√𝑎 + √4𝑏)(√𝑎 − 2√𝑏)
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    (Original post by error405)
    Simplify fully (√𝑎 + √4𝑏)(√𝑎 − 2√𝑏)
    So simplify
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    (Original post by error405)
    Simplify fully (√𝑎 + √4𝑏)(√𝑎 − 2√𝑏)
    First look at \sqrt{4b}. How can you simplify / write it in a different way?
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    (Original post by error405)
    ...
    Hi, please don't create duplicate threads - I have removed the thread you just created. If you still need help, please post all your working that you have tried.
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    (Original post by Notnek)
    Hi, please don't create duplicate threads - I have removed the thread you just created. If you still need help, please post all your working that you have tried.
    sorry couldn't find the thread

    √4B=2b right??
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    (Original post by error405)
    sorry couldn't find the thread

    √4B=2b right??
    Just checking sincce your original question isn't clear. Do you mean

    (\sqrt{a} +\sqrt{4} \ {b})(\sqrt{a}-2\sqrt{b})

    or

    (\sqrt{a} +\sqrt{4b})(\sqrt{a}-2\sqrt{b})

    I assumed it was the second one...
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    my working out:

    a+2√ab+2b√a-4b√b
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    (Original post by Notnek)
    First look at \sqrt{4b}. How can you simplify / write it in a different way?
    Multiply the brackets out to begin with
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    (Original post by Notnek)
    Just checking sincce your original question isn't clear. Do you mean

    (\sqrt{a} +\sqrt{4} \ {b})(\sqrt{a}-2\sqrt{b})

    or

    (\sqrt{a} +\sqrt{4b})(\sqrt{a}-2\sqrt{b})

    I assumed it was the second one...

    yes the 2nd one
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    (Original post by error405)
    sorry couldn't find the thread

    √4B=2b right??
    No. 2b would be square root 4b^2
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    (Original post by error405)
    yes the 2nd one
    Okay so \sqrt{4b} = \sqrt{4}\times \sqrt{b} = 2\sqrt{b}

    It then becomes

    (\sqrt{a} +2\sqrt{b})(\sqrt{a}-2\sqrt{b})

    Can you now try multiplying out the brackets? Post all your working if you get stuck.
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    (Original post by 12ksmith)
    Multiply the brackets out to begin with
    I recommended simplifying that term before expanding because then you have something of the form (x+y)(x-y) and it's easier to expand.
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    (Original post by Notnek)
    I recommended simplifying that term before expanding because then you have something of the form (x+y)(x-y) and it's easier to expand.

    Well yeah, you could simplify the left bracket to where root 4b becomes 2 root b. I guess that could make it a little simpler. But you would have to multiply out anyways.

    Personally I would find this easier to multiply out first then simplify from there.
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    (Original post by Notnek)
    Okay so \sqrt{4b} = \sqrt{4}\times \sqrt{b} = 2\sqrt{b}

    It then becomes

    (\sqrt{a} +2\sqrt{b})(\sqrt{a}-2\sqrt{b})

    Can you now try multiplying out the brackets? Post all your working if you get stuck.
    a-2√ab+2√ab-4√ b
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    (Original post by error405)
    a-2√b-2√ab+2√ab-4√ b
    a-4√ b
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    Thank you
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    (Original post by error405)
    a-4√ b
    Nearly but 2\sqrt{b}\times 2\sqrt{b} does not give 4\sqrt{b}. Have another go at this.

    Also please try to use brackets more in your posts e.g. instead of √ab, write √(ab) because √ab looks like \sqrt{a} \ b, which is not what you mean.
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    (Original post by Notnek)
    Nearly but 2\sqrt{b}\times 2\sqrt{b} does not give 4\sqrt{b}. Have another go at this.

    Also please try to use brackets more in your posts e.g. instead of √ab, write √(ab) because √ab looks like \sqrt{a} \ b, which is not what you mean.
    is it (4b) ?
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    (Original post by error405)
    is it (4b) ?
    Correct
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    a - (4b)
 
 
 
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