Y^2-10+30 Prove that the value of the expression must be positive.

Andres Abadia asked Jul 16, 2023

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Andres Abadia asked Jul 16, 2023

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18 votes

Answer:

Explanation:

$y^2-10y+30=\\y^2-2(y)(5)+5^2-5^2+30=\\(y-5)^2-25+30=\\(y-5)^2+5$

$(y-5)^2\geq 0\\\Rightarrow\ (y-5)^2+5 > 0\\Thus,\ y^2-10y+30 > 0$

David Tang answered Jul 22, 2023

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