Question

alguem sabe
x²+6x-15

Answer 1

$x^{2} +6x-15=0\\\\ a=1~;~b=6~;~c=-15\\\\\\ \Delta=b^2-4ac\to \Delta=6^2-4.1.(-15)\to \Delta=36+60\to \boxed{ \Delta=96}\\\\ x' \neq x''\\\\\\ x= \dfrac{-b\pm \sqrt{ \Delta} }{2a} \to~~ x= \dfrac{-6\pm \sqrt{96} }{2.1} \to~~ x= \dfrac{-6\pm 4\sqrt{ 6} }{2} \to~~\\\\\\ x'= \dfrac{-6+ 4\sqrt{ 6} }{2} \to~~ \boxed{x'= -3+ 2\sqrt{ 6}}\\\\\\ x''= \dfrac{-6- 4\sqrt{ 6} }{2} \to~~ \boxed{x''= -3- 2\sqrt{ 6}}\\\\\\\\ \large\boxed{S= \{-3- 2\sqrt{ 6}~~;~~-3+2\sqrt{ 6}\}}$