Answer:
[tex]\large\boxed{x=-7\sqrt2\ \vee\ x=7\sqrt2}[/tex]
Step-by-step explanation:
This is not an example for using a quadratic formula.
[tex]\dfrac{49}{2}-\dfrac{1}{4}x^2=0\qquad\text{subtract}\ \dfrac{49}{2}\ \text{from both sides}\\\\-\dfrac{1}{4}x^2=-\dfrac{49}{2}\qquad\text{multiply both sides by (-4)}\\\\x^2=(2)(49)\to x=\pm\sqrt{(2)(49)}\\\\x=\pm\sqrt2\cdot\sqrt{49}\\\\x=-7\sqrt2\ \vee\ x=7\sqrt2[/tex]