Respuesta :

Desmariesin

Answer:

2.8a      = 7.4

Step-by-step explanation:

5a² - 85 = 2.2a² - 30

      + 85 =          + 85

5a²        = 2.2a² +55

- 2.2a²   = -2.2a²

2.8a²     = 55

√2.8a²  = √55

2.8a      = 7.4