Resposta :
Olá
[tex]\frac{\left(7.5\cdot \:3\right)+\left(x\cdot \:2\right)+\left(5.5\cdot \:2\right)}{3+2+2}=6.5\\\\\frac{7\left(7.5\cdot \:3+x\cdot \:2+5.5\cdot \:2\right)}{3+2+2}=6.5\cdot \:7\\\\2x+33.5=45.5\\\\2x+33.5-33.5=45.5-33.5\\\\2x=12\\\\x = 12/2\\\\\huge\orange{\boxed{x = 6}}[/tex]
> 6,0 <
<> A nota de Fabiana em Geometria foi 6,0 <>
Espero ter ajudado!