Question

Determine os zeros das funções quadráticas:
a) f(x)= x² - x - 12
b) f(x)= x² - 5x + 4

Answer 1

a) x^2-x-12=0
delta=b^2-4ac
delta=(-1)^2-4.1.(-12)
delta=1+48
delta=49
x=-b-/+ raiz de delta/2a
x=-(-1)-7/2.1
x=1-7/2
x=-6/2
x=-3
x=-(-1)+7/2.1
x=1+7/2
x=8/2
x=4
S={-3, 4}
b) x^2-5x+4=0
delta=b^2-4ac
delta=(-5)^2-4.1.4
delta=25-16
delta=9
x=-b-/+ raiz de delta/2a
x=-(-5)-3/2.1
x=5-3/2
x=2/2
x=1
x=-(-5)+3/2.1
x=5+3/2
x=8/2
x=4
S={1, 4}