terça-feira, 2 de maio de 2017

Exercícios 9ºano
Equações


2 comentários:

  1. 10.1) +- 3
    10.2) +- 13
    10.3) +- -25/4

    Wilson Silva 9ºA2

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  2. 10.1-

    (x-3)^2 + 3 = 3(7-2x)

    (=) x^2 + 2(x-3) + (-3)^2
    (=) x^2 -6x + 9 + 3 = 3(7-2x)
    (=) x^2 -6x + 9 + 3 = 21-6x
    (=) x^2 = 21-9-3
    (=) x^2 = 9
    (=) x = +/- V9
    (=) x = +/- 3 V -3

    10.2

    x(x-3)/2 = -x

    (=) x(x-3) = 2(-x)
    (=) x^2 -3x = -2x
    (=) x^2 = -2x + 3x
    (=) x^2 = 1
    (=) x = +/- V1
    (=) x = +/- 1 V -1

    10.3

    (2x + 3) (2x - 3) = 16

    (=) 2x(2x-3) + 2x = 16
    (=) 4x^2 + 2x = 16
    (=) 4x^2 +2x = 16
    (=) 4.x.x + 2.x = 16
    (=) x(4x+2) = 16

    x = 16 V 4x + 2 = 16
    x = 16 V 4x = 16-2
    x = 16 V 4x = 14
    x = 16 V x = 14/4
    x = 16 V x = 7/2


    Rafael Valente
    9ºA2

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