Question

3) Resolua
as equaçoes s
a) 3x²-2x-1=0​

Answer 1

Resposta:

$\displaystyle\\Aplicando~a~f\'{o}rmula~de~Bhaskara~para~3x^{2}-2x-1=0~~\\e~comparando~com~(a)x^{2}+(b)x+(c)=0,~temos~a=3{;}~b=-2~e~c=-1\\\\\Delta=(b)^{2}-4(a)(c)=(-2)^{2}-4(3)(-1)=4-(-12)=16\\\\x^{'}=\frac{-(b)-\sqrt{\Delta}}{2(a)}=\frac{-(-2)-\sqrt{16}}{2(3)}=\frac{2-4}{6}=\frac{-2\div2}{6\div2}=-\frac{1}{3}\\\\x^{''}=\frac{-(b)+\sqrt{\Delta}}{2(a)}=\frac{-(-2)+\sqrt{16}}{2(3)}=\frac{2+4}{6}=\frac{6}{6}=1\\\\S=\{-\frac{1}{3},~1\}$