Question

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Answer 1

13) Temos que AD/AB = AE/AC => 6,4/4x = 2x/x² + 1 =. 6,4(x² + 1) = 4x.2x => 6,4x² + 6,4 = 8x² => 6,4x² - 8x² = -6,4 => -1,6x² = -6,4 => x² = -6,4/-1,6 => x² = 4 => x = √4 => x = 2. Logo, os lados do triângulo são:

AB = 2x + 6,4 = 2.2 + 6,4 = 4 + 6,4 = 10,4

AC = x² + 4x + 1 = 2² + 4.2 + 1 = 4 + 8 + 1 = 13

BC = 3x + 5 = 3.2 + 5 = 6 + 5 = 11

14) Perímetro = 12,5 + 13 + 20,3 = 45,8 cm

15)a) x/x + 14,7 = 10,5/21 => 21.x = 10,5(x + 14,7) => 21.x = 10,5.x + 154,35 => 21.x - 10,5.x = 154,35 => 10,5.x = 154,35 => x = 154,35/10,5 => x 14,7

b) x/21 = 4/7 => 7x = 21.4 => 7.x = 84 => x = 84/7 => x = 12

c) 2x/18 = 7/7 => 2x/18 = 1 => 2x = 18 => x = 18/2 => x = 9