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    Name:  help.PNG
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Size:  10.6 KBi need help with these. answers please
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    (Original post by ngunn)
    Name:  help.PNG
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Size:  10.6 KBi need help with these. answers please
    Which methods have you learnt for solving quadratics? Have you done any working so far?

    EDIT: Oops I just realised it says by bompleting the square!
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    (Original post by alow)
    Which methods have you learnt for solving quadratics? Have you done any working so far?

    EDIT: Oops I just realised it says by bompleting the square!
    i dont understand any of it
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    (Original post by ngunn)
    i dont understand any of it
    For the first one start by finding an expression of the form \left( x+a \right)^{2}+c where a and c are constants and is equal to x^{2}+18x-10

    So, \left( x+a \right)^{2}+c=x^{2}+18x-10

    HINT: Find a by halving the coefficient of the x term in the origional quadratic (which in the first question is 18).
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    are ok thanks
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    (Original post by ngunn)
    i dont understand any of it
    Don't you think you should speak to your teacher then?
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    (Original post by alow)
    For the first one start by finding an expression of the form \left( x+a \right)^{2}+c where a and c are constants and is equal to x^{2}+18x-10

    So, \left( x+a \right)^{2}+c=x^{2}+18x-10

    HINT: Find a by halving the coefficient of the x term in the origional quadratic (which in the first question is 18).
    can you give me the answer to the first one so i can see how it worked please
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    (Original post by ngunn)
    can you give me the answer to the first one so i can see how it worked please
    (x+a)^2+c=x^2+ \underbrace{2ax}_{18x} + \underbrace{a^2+c}_{-10}=x^{2}+18x-10. Hope that helped...
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    (Original post by ngunn)
    can you give me the answer to the first one so i can see how it worked please
    I'll give you the start:

    \left( x+a \right)^{2}+c=x^{2}+18x-10 \Rightarrow a=9



\Rightarrow \left( x+9 \right)^{2}+c=x^{2}+18x-10



\Rightarrow x^{2}+19x+81+c=x^{2}+18x-10

    Can you see how to continue this and find the values of x? If not, as Mr M said, it's probably better to go to your teacher.
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    (Original post by keromedic)
    (x+a)^2+c=x^2+ \underbrace{2ax}_{18x} + \underbrace{a^2+c}_{-10}=x^{2}+18x-10. Hope that helped...
    how do i get the two possible values for x from that
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    (Original post by ngunn)
    how do i get the two possible values for x from that
    I don't know what you're asking, sorry.
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    (Original post by ngunn)
    can you give me the answer to the first one so i can see how it worked please
    That looks like it's MyMaths. Have you tried doing the lesson on there?
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    (Original post by ngunn)
    how do i get the two possible values for x from that
    Because if you initially brought all the constants over two one side, then you know that (x+a)^2+c=0 and you can solve this (remembering the +- when square rooting) to find the two possible values of x.
 
 
 
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