Answer:
14.25 units
Step-by-step explanation:
Area of a square= [tex]l*b= (x-3)(x-3)=x^{2}-3x-3x+9=x^{2}-6x+9[/tex]
[tex]x^{2}-6x+9=126.5625[/tex]
[tex]x^{2}-6x-117.5625[/tex]
Solving the equation using quadratic equation then as attached
x=14.25 units
To prove
x-3=14.25-3= 11.25 units
area=11.25*11.25=126.5625 sq units
