Problem
$(a+b)^{2}=$
Solution
Step 1 ：Use the binomial theorem to expand $(a+b)^2$: $(a+b)^2 = \sum_{k=0}^2 {2 \choose k} a^{2-k} b^k$
Step 2 ：Simplify the expansion: $(a+b)^2 = a^2 + 2ab + b^2$ \[\boxed{a^2 + 2ab + b^2}\]
Step 1 ：Use the binomial theorem to expand $(a+b)^2$: $(a+b)^2 = \sum_{k=0}^2 {2 \choose k} a^{2-k} b^k$
Step 2 ：Simplify the expansion: $(a+b)^2 = a^2 + 2ab + b^2$ \[\boxed{a^2 + 2ab + b^2}\]
