x2 – 8x + 15 = 0 quadratic formula

Question

x2 – 8x + 15 = 0
quadratic formula

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Hailey 43 mins 2022-01-02T22:39:41+00:00 1 Answer 0 views 0

Answers ( )

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    2022-01-02T22:41:36+00:00

    The quadratic formula is x=(-b+-sqrt(b^2-4(a)(c)))/2a

    Using the quadratic formula, we get:

    x=(-(-8)+-sqrt((-8)^2-4(15)(1)))/2(1)

    x=(8+-sqrt(64-60))/2

    x=(8+-sqrt(4))/2

    x=(8+-2)/2

    x=10/2 and x=6/2

    x=5 and x=3

    We could do it way faster by completing the square:

    x^2-8x+15=0

    (x-5)(x-3)=0

    x=5 and x=3

    Hope both methods make sense! BTW, the +- thing means add or subtract

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