Question

2) Ache o valor de ∆:

a) x² - x - 20 = 0

b) x² - 3x -4 = 0

c) x² - 8x + 7 = 0

Answer 1

Resposta:

x² - x - 20 = 0

a=1 b= -1 c= -20

∆=b² -4.a.c

∆= -1²-4.1.-20

∆= 1+80

∆=81

b) x² - 3x -4 = 0

a= 1 b= -3 c=-4

∆=b² -4.a.c

∆= -3²-4.1.-4

∆= 9+16

∆=25

c) x² - 8x + 7 = 0

a=16 b= -8 c= 7

∆= b²-4.a.c

∆= -8²-4.1.7

∆= 64-28

∆=36