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Help with Simultaneous Equation

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    Hi,

    The answer to this is x = 13.

    10x + 26(x-3) = 390.

    Why? What do I do with the brackets?

    Thanks!
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    10x+26(x-3)=390
    10x+26x-70=390 <----- expand the brackets, make sure to multiply 26 by -3
    36x = 460 <------ rearrange to get x terms on one side by adding 70
    x = 460/36 <------ divide 460 by 36 to get x on its own
    x = 12.77777778
    x = 13
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    (Original post by ℓove)
    10x+26(x-3)=390
    10x+26x-70=390 <----- expand the brackets, make sure to multiply 26 by -3
    36x = 460 <------ rearrange to get x terms on one side by adding 70
    x = 460/36 <------ divide 460 by 36 to get x on its own
    x = 12.77777778
    x = 13
     26 \times -3 \neq -70

    expand and rearrange for x.
    26(x-3) = 26x + 26(-3)
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    (Original post by ℓove)
    ...
    x = 12.77777778
    x = 13
    If x=12.77777778 then how does it follow that x=13?

    Does 12.77777778=13??

    Just wanted to point that out because it was bothering me...
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    Also 26 \cdot (-3) \not= -70
 
 
 
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