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Find the discriminant of the quadratic 5x^2 - 2x + 8 - 2x^2 + 6x + 2 - 2x^2 + 4x - 1.

 Jun 20, 2024

Best Answer 

 #2
avatar+1230 
+1

Tottenham10, you did a great job with simplifying the quadratic, but there was one tiny mistake. 

The descriminant is \(b^2-4ac\), not \(\sqrt{b^2-4ac}\). Other than that, you're good!

 

So, now we...

 

First, let's combine all like terms. We get;

\(x^{2}+8x+9\)

 

Now, the decriminant is \(b^2-4ac\) for any quadratics in the form of \(ax^2+bx+c\)

 

Thus, plugging in the numbers in the quadratic we have, we get

\(8^2-4(1)(9) \\ = 64- 36\\ =28\)

 

So 28 is our answer. 

 

Thanks! :)

 Jun 20, 2024
edited by NotThatSmart  Jun 20, 2024
 #1
avatar+42 
-1

If we combine all the like terms, the expression turns into \(x^2+8x+9\). The discriminant is \(\sqrt{b^2-4ac}\), so if we just plug in the values, we get \(\sqrt{64-36}=\sqrt{28}=2\sqrt{7}\).

 

Feel free to tell me if I made a mistake! :D

 Jun 20, 2024
 #2
avatar+1230 
+1
Best Answer

Tottenham10, you did a great job with simplifying the quadratic, but there was one tiny mistake. 

The descriminant is \(b^2-4ac\), not \(\sqrt{b^2-4ac}\). Other than that, you're good!

 

So, now we...

 

First, let's combine all like terms. We get;

\(x^{2}+8x+9\)

 

Now, the decriminant is \(b^2-4ac\) for any quadratics in the form of \(ax^2+bx+c\)

 

Thus, plugging in the numbers in the quadratic we have, we get

\(8^2-4(1)(9) \\ = 64- 36\\ =28\)

 

So 28 is our answer. 

 

Thanks! :)

NotThatSmart Jun 20, 2024
edited by NotThatSmart  Jun 20, 2024

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