Question

Find the discriminant of the quadratic equation below.

x^2 + 4x + 9 = 0

Answer 1

For general quadratic equation,
Ax^2 +Bx+C
discriminant is given as \[\sqrt{B^{2}-4*A*C}\]

Answer 2

\[1x^2+4x+9=0\]
\[A=1, B=4, C=9\]
Use the equation above to find the discriminant

Answer 3

im gonna ask a stupid question but what is a discriminant?

Answer 4

It aint a stupid question
The discriminant is an equation that tells us how many real roots our polynomial has
So if the discriminant is greater than 0 then our polynomial has 2 real roots
If it equals 0 then it has only one real root
If it equals less than 0 then there are no real roots

Answer 5

The equation of the discriminant is : \[\sqrt{B^{2}-4*A*C}\]
I forgot to mention that a polynomial is an equation with the highest degree being 2: \[y=3x^{\color{orange}2}+5x+3\]
Now a polynomial in standard form looks as follows: \[Ax^2+Bx+C=0\] where A, B and C are numerical values
So in our case the equation is \[\color{orange}{1}x^2+\color{orange}{4}x+\color{orange}{9}=0\]
So our A=1, B=4 and C=9

Answer 6

Now we need to plug this info into our discriminant equation

\[Discriminant= \sqrt{4^2-4*(1)(9)}\]
\[=\sqrt{16-36}\]
\[=-20\]

Answer 7

thank you so much!

Answer 8

Its kinda simple once you memorize the equation

Answer 9

yeah it sure is

Answer 10

LOL GL