Answer: Option 'B' is correct.
Step-by-step explanation:
Since we have given that
[tex]x+17=38[/tex]
We need to find the value of 'x':
For which , we will subtract 17 from both the sides , and get
[tex]x+17-17=38-17\\\\x=21[/tex]
Hence, we were using "Subtraction property of equality" which states that same number is deducted from both the sides of equality.
Thus, option 'B' is correct.