Question

Dada a função f:R⇒R definida por f(x) = x² - 5x + 6, calcule os valores reais de x para que se tenha: a) f(x)= 0 b) f(x)=12

Answer 1

f(x)=x^2-5x+6
a) f(x)=0
x^2-5x+6=0
delta=b^2-4ac
delta=(-5)^2-4.1.6
delta=25-24
delta=1
x=-b-/+ raiz de delta/2a
x=-(-5)-1/2.1
x=5-1/2
x=4/2
x=2
x=-(-5)+1/2.1
x=5+1/2
x=6/2
x=3
b) f(x)=12
x^2-5x+6=12
x^2-5x+6-12
x^2-5x-6=0
delta=b^2-4ac
delta=(-5)^2-4.1.(-6)
delta=25+24
delta=49
x=-b-/+ raiz de delta/2a
x=-(-5)-7/2.1
x=5-7/2
x=-2/2
x=-1
x=-(-5)+7/2.1
x=5+7/2
x=12/2
x=6