Question

a) x(x-1)=16-x
b) x(x-2)=5x
c) 2x(x+1)-7x=x²+x
d) x(x+7)-3x=4x
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Answer 1

Resposta:

Explicação passo a passo:

a)x(x - 1) = 16 - x

x² - x = 16 - x

x² -x + x - 16 = 0

x² - 16 = 0

x² = 16

x = + ou -√16

x = + ou - 4

S = {-4;+4}

b)x(x - 2) = 5x

x² - 2x - 5x = 0

x² -7 x = 0

x(x - 7) = 0

x = 0

x - 7 = 0

x = 7

S = [0;7}

C)2X(X + 1) - 7X = X² + X

2X² + 2X  - 7X  = X² - X

2X² - X² - 5X + X = 0

X² - 4X = 0

X(X - 4) = 0

X = 0

X - 4 = 0

X = 4

S = {0;4}

d)x(x + 7) - 3x = 4x

x² + 7x - 3x = 4x

x² + 4x = 4x

x² +4x -4x = 0

x² = 0

x = √0 = 0

S = {0}