Respuesta :

1. [tex]F = \frac{a+b+c}{3} [/tex]
2. [tex]F3 = a+b+c[/tex]
3. [tex]F3 - a = b+c[/tex]
4. [tex]F3 - a - c = b[/tex]

1. Start
2. Multiply both sides by 3
3. Subtract a from both sides
4. Subtract c from each sides