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A asked in Science & MathematicsMathematics · 6 months ago

√(4a²) = 2a?

In proving the quadratic formula I read this

..

(x + b/(2a))² = (b² - 4ac)/(4a²)

x + b/(2a) = (±√(b² - 4ac))/(2a)

Why did they do √(4a²) = 2a? Shouldn't it be 2|a|?

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  • 6 months ago
    Favorite Answer

    That doesn't matter because there's already a +/- in the numerator. So it works either way.

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  • 6 months ago

    You are correct it is technically:

    ±2a

    But as Jeff stated, since you already have a ± in the numerator, adding one in the denominator doesn't change anything.

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