Question

2. quais as raízes da função f(x) = x² +8x -9 * 10 pontos (1 , 8) (1, -8) (1 , -9) ( 2, 16) ​

Answer 1

Resposta:

(1, -9)

Explicação passo a passo:

$\displaystyle Aplicando~a~f\acute{o}rmula~de~Bhaskara~para~x^{2}+8x-9=0~~e~comparando~com~(a)x^{2}+(b)x+(c)=0,~determinamos~os~coeficientes:~\\a=1{;}~b=8~e~c=-9\\\\C\acute{a}lculo~do~discriminante~(\Delta):&\\&~\Delta=(b)^{2}-4(a)(c)=(8)^{2}-4(1)(-9)=64-(-36)=100\\\\C\acute{a}lculo~das~raizes:&\\x^{'}=\frac{-(b)-\sqrt{\Delta}}{2(a)}=\frac{-(8)-\sqrt{100}}{2(1)}=\frac{-8-10}{2}=\frac{-18}{2}=-9\\\\x^{''}=\frac{-(b)+\sqrt{\Delta}}{2(a)}=\frac{-(8)+\sqrt{100}}{2(1)}=\frac{-8+10}{2}=\frac{2}{2}=1$