[latex] sqrt{- x^{2} -17x-72} [/latex][latex]- x^{2} -17x-72 geq 0[/latex][latex] x^{2} +17x+72 leq 0[/latex][latex]D=289-288=1[/latex][latex] x_{1} = frac{-17+1}{2} =-8, x_{2} = frac{-17-1}{2} =-9[/latex]x∈[-9;-8]