Respuesta :

Americ
x= a number

29 - 2x= 21
subtract 29 from both sides
-2x= -8
divide both sides by -2
x= 4

CHECK:
29 - 2x= 21
29 - 2(4)= 21
29 - 8= 21
21= 21

ANSWER: The number is 4.

Hope this helps! :)