Respuesta :

Advent5647

Answer:

15

Step-by-step explanation:

Step 1:

b + 6 = 21        Equation

Step 2:

b = 21 - 6      Subtract 6 on both sides

Step 3:

b = 15    Subtract

Step 4:

15 + 6 = 21     Check Answer

Answer:

b = 15

Hope This Helps :)