Use the quadratic formula where -15 = a, 7 = b, 23 = c: [tex]\frac{-b +- \sqrt{b^2 - 4ac}}{2a}[/tex]
Plug in the values: [tex]\frac{-7 +- \sqrt{7^2 - 4(-15)(23)}}{2(-15)}[/tex]
And get: [tex]\frac{-7 +- \sqrt{49 +1380}}{-30}[/tex]
Which simplifies to: [tex]\frac{-7 +- \sqrt{1429}}{-30} = (-7 + 37.8021163)/-30 OR (-7 - 37.8021163)/-30 = 30.8021163/30 OR -44.8021163/30[/tex]
Those are approximately 1 and -1.5
