The coefficient of $x^2$ in the expansion of $(1 + x)^4$ equals _____.
Step-by-Step Solution
Key Concept: Write the general term $T_{r+1} = \binom{4}{r} x^r$, set $r = 2$, and evaluate the resulting binomial coefficient.
The detailed step-by-step mathematical proof is available inside the Mathbee app workspace.
Correct Answer: 6