Question

Resolva as equações 2×2-7×-15=0

Answer 1

Resposta:

$S=\{-\frac{3}{2},~5\}$

Explicação passo-a-passo:

$Aplicando~a~f\'{o}rmula~de~Bhaskara~para~2x^{2}-7x-15=0~~\\e~comparando~com~(a)x^{2}+(b)x+(c)=0,~temos~a=2{;}~b=-7~e~c=-15\\\\\Delta=(b)^{2}-4(a)(c)=(-7)^{2}-4(2)(-15)=49-(-120)=169\\\\x^{'}=\frac{-(b)-\sqrt{\Delta}}{2(a)}=\frac{-(-7)-\sqrt{169}}{2(2)}=\frac{7-13}{4}=\frac{-6}{4}=-\frac{3}{2}\\\\x^{''}=\frac{-(b)+\sqrt{\Delta}}{2(a)}=\frac{-(-7)+\sqrt{169}}{2(2)}=\frac{7+13}{4}=\frac{20}{4}=5\\\\S=\{-\frac{3}{2},~5\}$