[tex]7x^2+8x+1=0\\\\a=7;\ b=8;\ c=1\\\\\Delta=b^2-4ac;\ if\ \DElta > 0\ then\ x_1=\frac{-b-\sqrt\Delta}{2a}\ and\ x_2=\frac{-b+\sqrt\Delta}{2a}\\\\\Delta=8^2-4\cdot7\cdot1=64-28=36;\ \sqrt\Delta=\sqrt{36}=6\\\\x_1=\frac{-8-6}{2\cdot7}=\frac{-14}{14}=-1;\ x_2=\frac{-8+6}{2\cdot7}=\frac{-2}{14}=-\frac{1}{7}\\\\Answer:x=-1\ \vee\ x=-\frac{1}{7}[/tex]