Respuesta :

Answer:

x = a number

7 + 2x = 21

Subtract 7 from both sides

2x = 14

Divide both sides by 2

x = 7

7 is the only number that makes this sentence true.

Step-by-step explanation:

Answer:

7

Step-by-step explanation:

Do the steps in reverse

Subtract 7 from 21

14

Then divide by 2

7

Hope this helps :)

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