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Maths - Completing the square watch

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    I'm confused about this one past paper question.
    "Find the values of a and b such that x^2 +10x +18 = (x-a)^2 +b"
    I worked out that it is (x+5)^2 -25+18. ---> (x+5)^2 - 7. However, the answer says "a=5, b=-7". Why is a=5 and not -5? It says in the question (x-a)^2, so it says -a, therefore it should be -5? Same goes for b, answer say -7 but in the question it says (x-a)^2 ***+b***. So it should be +7.??? Please help ty ty
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    There has been an awakening
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    (Original post by TheFarmerLad)
    There has been an awakening
    .....?? What do you mean by that?:confused:
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    (Original post by Perfection Ace)
    .....?? What do you mean by that?:confused:
    Your answer is correct, so either the ms is wrong or you miswrote the question..?
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    Your answer is correct, I think there could be a typo in the question
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    Okay, thank you to both of you. =D
 
 
 
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