Question

Dada a f(x) = 3x²-18 x+24, qual o zero ou raiz da função quadrafica f(x)=0

Answer 1

$f(x)=0\ \therefore\ 3x^2-18x+24=0\ \therefore\\\\ x^2-6x+8=0\ \therefore\ a=1,\ b=-6,\ c=8\\\\ x=\dfrac{-b\pm\sqrt{b^2-4ac}}{2a}=\dfrac{-(-6)\pm\sqrt{(-6)^2-4(1)(8)}}{2(1)}=$

$=\dfrac{6\pm\sqrt{4}}{2}=3\pm1\ \therefore\ \boxed{x=2}\ \text{ou}\ \boxed{x=4}$