Answer:
x = 10 is your answer
- Explain -
Step 1: subtract 1 from both sides (subtraction of equality)
which will give us:
2x = 21 - 1
which equals to
2x = 20
Step 2: Divide both sides by 2
which is
2x/2 = 20/2
2/2 = 1 and 20/2 = 10
Therefore the answer is x = 10