Question

As raízes da função f(x)=x²-5x+4 definida de R em R.

a) S={7,2};
b) S={2,3};
c) S={7,3};
d) S={1,4};

Answer 1

f(x)= x^2-5x+4
x^2-5x+4=0
delta=b^2-4.a.c
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}
letra d