Mathematics

# 9x^2+5x-1=0 use quadratic formula to solve for x

$9x^2+5x-1=0\\ \Delta=5^2-4\cdot 9\cdot (-1)=25+36=61\\ \sqrt{\Delta}=\sqrt{61}\\ x_1=\frac{-5-\sqrt{61}}{2\cdot9}=-\frac{5+\sqrt{61}}{18}\\ x_2=\frac{-5+\sqrt{61}}{2\cdot9}=-\frac{5-\sqrt{61}}{18}$