Răspuns:
Explicație pas cu pas:
30.
(x + 1)^2 + (3x - 1)^2 = (x - 3)^2 + (3x + 4)^2
x^2 + 2x + 1 + 9x^2 - 6x + 1 = x^2 - 6x + 9 + 9x^2 + 24x + 16
10x^2 - 4x + 2 = 10x^2 + 18x + 25
18x + 4x = 2 - 25
22x = -23
x = -23/22
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31.
Produsul mezilor = Produsul extremilor
(x - 2)(6x + 5) = (3x - 2)(2x + 1)
6x^2 + 5x - 12x - 10 = 6x^2 + 3x - 4x -2
6x^2 - 7x - 10 = 6x^2 - x - 2
7x - x = 2 - 10
6x = -8
x = -8/6 = -4/3
