The quadratic equation given is,
[tex]r^2+18r+81=0[/tex]
Using discriminant(d) formula to obtain the number of real solution
The formula is,
[tex]d=b^2-4ac[/tex]
Given:
[tex]a=1,b=18,c=81[/tex]
Therefore,
[tex]\begin{gathered} d=18^2-4(1)(81)=324-324=0 \\ \therefore d=0 \end{gathered}[/tex]
Since,
[tex]\begin{gathered} d=0 \\ \therefore It\text{ has one real solution, but equal root.} \end{gathered}[/tex]
Hence, it has one real solution.
