Question

preciso de dois numeros no qual a soma dos dois é -2 e a multiplicação dos dois dê -4

Answer 1

$Sejam\ x\ e\ y\\\\ x + y = - 2\\x = -2 - y\\\\x\cdot{y} = - 4\\\\(-2 - y) \cdot{y} = - 4\\-2y - y^2 = - 4\\y^2 + 2y - 4 = 0\\\\a=1\ \ \ \ b=2\ \ \ \ c=-4\\\\\triangle=b^2-4ac\\\triangle=(2)^2-4\cdot(1)\cdot(-4)\\\triangle=4+16\\\triangle=20\\\\\\y= \dfrac{-b \frac{+}{-} \sqrt{\triangle}}{2a}\\\\\\y= \dfrac{-2 \frac{+}{-}2 \sqrt{5} }{2}\\\\\\y'= \dfrac{-2+2 \sqrt{5} }{2} \\\\\\y'={-1+ \sqrt{5}}\\\\\\y"= \dfrac{-2-2 \sqrt{5} }{2}\\\\\\y"=-1-\sqrt{5}\\\\\\\boxed{S=\{(-1+ \sqrt{5},-1- \sqrt{5} )\}}$