Answer: [tex]\frac{9}{2} | -\frac{9}{2}[/tex]
Step-by-step explanation:
[tex]81 -4x^{2} = 0\\ -4x^{2} +81 =0\\ (2x +9)(-2x+9)=0\\ 2x +9 = 0 | -2x+9=0\\ 2x = -9| -2x = -9\\ \frac{2x}{2} = \frac{9}{2} | \frac{2x}{2} = \frac{-9}{2}\\ x = \frac{9}{2} | x = -\frac{9}{2}[/tex]
