Respuesta :

Answer:

[tex]b=3A-a-c[/tex]

Step-by-step explanation:

[tex]$A=\frac{a+b+c}{3} $[/tex]

Multiply both sides by 3

[tex]$3A=a+b+c $[/tex]

Add [tex]-b-c[/tex] both sides

[tex]3A-a-c=b[/tex]

[tex]b=3A-a-c[/tex]