To find roots we need to solve the equation
x² +5x+7=0
a=1, b=5, c=7
D= b² - 4ac = 25 -4*1*7= 25 - 28 =-3
Because the D<0, there are no real roots, only imaginary roots.
[tex]x= \frac{-b+/- \sqrt{D} }{2a}
\\ \\x= \frac{-5+/- \sqrt{-3} }{2*1}
\\ \\ x=-2.5+ \frac{ \sqrt{3} }{2}i
\\ \\x=-2.5- \frac{ \sqrt{3} }{2}i [/tex]
