Question

What is the discriminant of the polynomial?2x^2+5x-8​

Answer 1

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Let's find the discriminant (D) of the given polynomial ~

Let's compare the given quadratic expression with general expression ~

$\boxed{ \boxed{ \sf {ax}^{2} +b x + c }}$

we get ;

• $\sf \: a = 2$
• $\sf \: b = 5$
• $\sf \: c = - 8$

Now, use the following formula :

$\qquad \sf \dashrightarrow \: D = b² - 4ac$

$\qquad \sf \dashrightarrow \: D = (5) {}^{2} - (4 \times 2 \times ( - 8))$

$\qquad \sf \dashrightarrow \: D = 25 - ( - 64)$

$\qquad \sf \dashrightarrow \: D = 25 + 64$

$\qquad \sf \dashrightarrow \: D = 89$

Therefore, discriminant of the given quadratic expression is 89