Question

Complete the square 3x^2+12x-1 show working

Answer 1

`3x^2+12x-1\\\\a=3;\ b=12;\ c=-1\\\\\Delta=b^2-4ac\to\Delta=12^2-4\cdot3\cdot(-1)=144+12=156\\\\x=(-b\pm\sqrt\Delta)/(2a)\\\\\sqrt\Delta=√(156)=√(4\cdot39)=\sqrt4\cdot√(39)=2√(39)\\\\x=(-12\pm2√(39))/(2\cdot3)=(-6\pm√(39))/(3)\\\\3x^2+12x-1=3(x-(-6-√(39))/(3))(x-(-6+√(39))/(3))\\\\=\boxed{3(x+(6+√(39))/(3))(x+(6-√(39))/(3))}`