Question

Which two values of x are roots of the polynomial below? x2 + 5x + 7

Answer 1

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.

$x= \frac{-b+/- \sqrt{D} }{2a} \\ \\x= \frac{-5+/- \sqrt{-3} }{2*1} \\ \\ x=-2.5+ \frac{ \sqrt{3} }{2}i \\ \\x=-2.5- \frac{ \sqrt{3} }{2}i$