Question

21 + p = 42

Answer 1

Solve for p:
p+21 = 42
Isolate terms with p to the left hand side.
Subtract 21 from both sides:
p+(21-21) = 42-21
Look for two terms that sum to zero.
21-21 = 0:
p = 42-21
Evaluate 42-21.
42-21 = 21:
Answer: |
| p = 21