Wat is 7x² + 4x - 5= 0
\(7x^2+4x-5=0\\ \Delta=4^2-4\cdot7\cdot(-5)=16+140=156\\ \sqrt{\Delta}=\sqrt{156}=2\sqrt{39}\\ x=\dfrac{-4\pm2\sqrt{39}}{2\cdot7}=\dfrac{-2\pm\sqrt{39}}{7}\)
Answer and workings in the attachment below.
