Respuesta :

Isolate the y

add 7 to both sides

y - 7  = 21

y - 7 (+7) = 21 (+7)

y = 21 + 7 

y = 28

28 is your answer

hope this helps


Answer:

28

Step-by-step explanation:

just plug it in

28 - 7 = 21

:)