Answer :

[tex]2x^2-7=74\\ 2x^2=81\\ x^2=\dfrac{81}{2}\\ x=-\sqrt{\dfrac{81}{2}} \vee x=\sqrt{\dfrac{81}{2}}\\ x=-\dfrac{9}{\sqrt2} \vee x=\dfrac{9}{\sqrt2}}\\ x=-\dfrac{9\sqrt2}{2} \vee x=\dfrac{9\sqrt2}{2}}\\[/tex]