Answer:
[tex]\underline{x\in\left\{-6\,,\ 1\right\}}[/tex]
Step-by-step explanation:
[tex]x^2+5x-6=0\\\\a=1\,,\ \ b=5\,,\ \ c=-6\\\\x_1=\dfrac{-5-\sqrt{5^2-4\cdot1\cdot(-6)}}{2\cdot1}=\dfrac{-5-\sqrt{25+24}}2=\dfrac{-5-\sqrt{49}}2=\dfrac{-5-7}2=-6\\\\x_2=\dfrac{-5+\sqrt{5^2-4\cdot1\cdot(-6)}}{2\cdot1}=\dfrac{-5+7}2=1[/tex]
