Question

Calculate the discriminant to determine the number of real roots.



y = x2 + 3x + 9





How many real roots does the equation have?



A.
two real roots


B.
no real roots


C.
one real root


D.
no solution to the equation

Answer 1

@LynFran

Answer 2

\[\sqrt{b^2-4ac}=\sqrt{3^2-4*9*1}\]

Answer 3

so A there are two real roots?

Answer 4

Ok, I will tell you this.

The discriminant for any quadratic in a form of: \(\color{black}{ \displaystyle y=a{\rm x}^2+b{\rm x}+c }\)
is: \(\large\color{black}{ \displaystyle {\rm D}=\sqrt{b^2-4ac} }\)

Answer 5

So, if the discriminant is:

an integer - then you can factor the quadratic
a real number (not 0, and not integer) - then you just have 2 real roots.
an imaginary number (that results from a negative in a square root) - then no real roots, rather, only 2 imaginary roots.

Answer 6

for people that see this in the future its B