Question

A)−2x − 3x + x − 5 + 3x + 1 = −x − 4
B) 2 (x − 5) + 3 (3x + 1) = 2x − 10 + 9x + 3 = 11x − 7
C) (x − 5). (3x + 1) − (−3) = 3x² + x − 15x − 5 + 3 = 3x² − 14x − 2
D) −2x − 3x − x − 5 = −5x − x + 5 = 6x + 5

Answer 1

Resposta:

A) x = - 4

B) x = - 0,63

C) x' = 4,51 e x" = 0,147

D) x = - 0,83

Explicação passo-a-passo:

A) - 2x − 3x + x − 5 + 3x + 1 = − x − 4

- x - 4

( o x não pode ficar negativo, então multiplica-se tudo por (-1) )

x + 4 = 0

x = - 4

B) 2 (x − 5) + 3 (3x + 1) = 2x − 10 + 9x + 3 = 11x − 7

11x = - 7

x = - 7 / 11

x = aprox - 0,63

C) (x − 5). (3x + 1) − (−3) = 3x² + x − 15x − 5 + 3 = 3x² − 14x − 2

3x² - 14x - 2

delta = b² - 4.a.c

delta = (-14)² - 4.3.(-2)

delta = 196 - 24

delta = 172

x = ( - b +- raiz de delta ) / 2.a

x = ( - ( - 14) +- raiz de 172) / 2 . 3

x = ( 14 +- aprox. 13, 11 ) / 6

x' = ( 14 + 13,11 ) / 6

x' = 27,11 / 6 = aprox. 4,51

x" = ( 14 - 13,11 ) / 6

x" = 0,89 / 6 = aprox. 0,147

D) −2x − 3x − x − 5 = −5x − x + 5 = 6x + 5

6x + 5

6x = - 5

x = - 5 / 6 = aprox. - 0,83