Heya !
Given expression -
[tex]3 {x}^{2} + 25 = 73[/tex]
Subtracting 25 both sides ,
[tex]3 {x}^{2} + 25 - 25 = 73 - 25 \\ \\ 3 {x}^{2} = 48[/tex]
Dividing by 3 on both sides ,
[tex] \frac{3 {x}^{2} }{3} = \frac{48}{3} \\ \\ {x}^{2} = 16[/tex]
Therefore ,
[tex]x = + \: 4 \: \: \: \: or \: \: - 4 \: \: \: \: \: \: \: Ans.[/tex]