[tex]▪▪▪▪▪▪▪▪▪▪▪▪▪ {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪[/tex]
Let's find the discriminant (D) of the given polynomial ~
Let's compare the given quadratic expression with general expression ~
[tex] \boxed{ \boxed{ \sf {ax}^{2} +b x + c }}[/tex]
we get ;
Now, use the following formula :
[tex]\qquad \sf \dashrightarrow \: D = b² - 4ac[/tex]
[tex]\qquad \sf \dashrightarrow \: D = (5) {}^{2} - (4 \times 2 \times ( - 8))[/tex]
[tex]\qquad \sf \dashrightarrow \: D = 25 - ( - 64)[/tex]
[tex]\qquad \sf \dashrightarrow \: D = 25 + 64[/tex]
[tex]\qquad \sf \dashrightarrow \: D = 89[/tex]
Therefore, discriminant of the given quadratic expression is 89