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What is the discrimant of x^2 +x-2=0

User Ginna
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1 Answer

4 votes

Answer:

Discriminant = 9.

Explanation:

Discriminant


\boxed{b^2-4ac}\quad\textsf{when}\;ax^2+bx+c=0


\textsf{when $b^2-4ac > 0 \implies$ two real roots}.


\textsf{when $b^2-4ac=0 \implies$ one real root}.


\textsf{when $b^2-4ac < 0 \implies$ no real roots}.

Given function:


x^2+x-2=0

Therefore:

  • a = 1
  • b = 1
  • c = -2

Substitute the values of a, b and c into the discriminant formula:


\begin{aligned} \implies b^2=4ac&amp;=(1)^2-4(1)(-2)\\&amp;=1-4(-2)\\&amp;=1+8\\&amp;=9\end{aligned}

Therefore, the discriminant of the given function is 9.

As the discriminant is greater than zero, this implies that there are two real roots.

User Gege
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