Question

How do you do 
`x^(2) -9x=15`

Answer 1

`x^2-9x=15\\x^2-9x-15=0\\a=1;\ b=-9;\ c=-15\\\Delta=b^2-4ac\to\Delta=(-9)^2-4(1)(-15)=81+60=141\\\\x=(-b\pm\sqrt\Delta)/(2a)\to x=(9\pm√(141))/(2)`