[tex]x^2+38x-84 =0 \\ \\a=1 , \ \ b=38, \ \ c=-84 \\ \\x _{1}=\frac{-b-\sqrt{b^2-4ac}}{2a}=\frac{-38-\sqrt{38^2-4 \cdot 1 \cdot (-84)}}{2 }=\frac{-38-\sqrt{1444+336}}{2 }=\\ \\=\frac{-38-\sqrt{1780}}{2 }= \frac{-38-\sqrt{4\cdot 445}}{2 }= \frac{-38-2\sqrt{ 445}}{2 }= \frac{2(-19- \sqrt{ 445})}{2 }=-19- \sqrt{ 445}[/tex]
[tex]x _{2}=\frac{-b+\sqrt{b^2-4ac}}{2a}= \frac{2(-19+ \sqrt{ 445})}{2 }=-19+\sqrt{ 445}[/tex]
