Question

Resolva as equações do 2º grau

x²+3x-10=0

Answer 1

$x^2+3x-10=0\\\\ a=1;~b=3;~c=-10\\\\\\ \Delta=b^2-4ac\to \Delta=3^2-4.1.(-10)\to \Delta=9+40\to \boxed{\Delta=49}\\\\ x' \neq x''\\\\\\ x= \dfrac{-b\pm \sqrt{\Delta} }{2a} \to~~ x= \dfrac{-3\pm \sqrt{49} }{2.1} \to~~ x= \dfrac{-3\pm 7 }{2} \to~~ \\\\\\ x'= \dfrac{-3+7 }{2} \to~~ x'= \dfrac{4 }{2} \to~~ \boxed{x'=2}\\\\\\ x''= \dfrac{-3-7 }{2} \to~~ x''= \dfrac{-10 }{2} \to~~ \boxed{x''=-5}\\\\\\\\ \large\boxed{\boxed{S=\{-5~;~2\}}}$

Answer 2

a=1 b=3 c=-10
▲=3(ao quadrado)-4x1x (-10)
▲=9+40
▲=49

x=-3+ou- (raiz de 49) sobre 2x1
x=-3+ou-7 (sobre 2)
x'=-10/2= -5
x"=4/2=2