Question

x² - 12X – 189 =0

a) Identifique os coeficientes a, bec.
b) Calcule o discriminante A= b2–4ac
c) Determine o valor de x .X​

Answer 1

Resposta:

a) a=1; b= -12 e c= -189

b) Δ = 900

c) x'= -9 e x"=21

Explicação passo-a-passo:

$Aplicando~a~f\'{o}rmula~de~Bhaskara~para~x^{2}-12x-189=0~~\\e~comparando~com~(a)x^{2}+(b)x+(c)=0,~temos~a=1{;}~b=-12~e~c=-189\\\\\Delta=(b)^{2}-4(a)(c)=(-12)^{2}-4(1)(-189)=144-(-756)=900\\\\x^{'}=\frac{-(b)-\sqrt{\Delta}}{2(a)}=\frac{-(-12)-\sqrt{900}}{2(1)}=\frac{12-30}{2}=\frac{-18}{2}=-9\\\\x^{''}=\frac{-(b)+\sqrt{\Delta}}{2(a)}=\frac{-(-12)+\sqrt{900}}{2(1)}=\frac{12+30}{2}=\frac{42}{2}=21\\\\S=\{-9,~21\}$