Question

Não consigo resolver está questão -4x²+2x+12=0

Answer 1

Resposta:

x=2 ou x= -3/2

Explicação passo-a-passo:

-4x²+2x+12=0  (÷2)

-2x²+x+6=0

$\displaystyle Aplicando~a~f\'{o}rmula~de~Bhaskara~para~-2x^{2}+1x+6=0~~\\e~comparando~com~(a)x^{2}+(b)x+(c)=0,~temos~a=-2{;}~b=1~e~c=6\\\\\Delta=(b)^{2}-4(a)(c)=(1)^{2}-4(-2)(6)=1-(-48)=49\\\\x^{'}=\frac{-(b)-\sqrt{\Delta}}{2(a)}=\frac{-(1)-\sqrt{49}}{2(-2)}=\frac{-1-7}{-4}=\frac{-8}{-4}=2\\\\x^{''}=\frac{-(b)+\sqrt{\Delta}}{2(a)}=\frac{-(1)+\sqrt{49}}{2(-2)}=\frac{-1+7}{-4}=\frac{6\div2}{-4\div2}=-\frac{3}{2}\\\\S=\{2,~-\frac{3}{2}\}$