Question

2. Determine os valores dos coeficientes a, be c?
a) f(x) = 2x2 + 10x + 12?
b) f(x) = x2 + 16x + 39?
c) h(x) = - 4x2 + 5

Me ajudem

Answer 1

a) f(x) = 2x² + 10x + 12

∆ = b² - 4.a.c

∆ = 10² - 4 2 12

∆ = 100 - 96

∆ = 4

x = - b ± √∆ / 2.a

x = - (10) ± √4 / 2.2

x = -10 ± 2 / 4

x' = -10 + 2 / 4 = -8/4 = -2

x" = -10 - 2 / 4 = -12/4 = -3

b) f(x) = x² + 16x + 39

∆ = b² - 4.a.c

∆ = 16² - 4.1.39

∆ = 256 - 156

∆ = 100

x = - b ± √∆ / 2.a

x = - 16 ± √100 / 2.1

x = -16 ± 10 / 2

x' = -6/2 = -3

x" = -16-10 = -26/2 = -13

c) h(x) = - 4x² + 5

∆ = b² - 4.a.c

∆ = 0² - 4 (-4) 5

∆ = 0 + 80

∆ = 80