Question

x 2 − 3x − 18 = 0 (a= 1; b =-3; c=-18)

Answer 1

Resposta:

x²-3x-18=0

a=1

b=-3

c=-18

∆=b²-4.a.c

∆=(-3)²-4.1.-18 = 9+72 = 81

$x = \frac{ - ( - 3) + \sqrt{81} }{2 \times 1} = \frac{3 + 9}{2} = \frac{12}{2} = 6$

$x = \frac{ - ( - 3) - \sqrt{81} }{2 \times 1} = \frac{3 - 9}{2} = \frac{ - 6}{2} = - 3$

raízes -3 e 6