1. **State the problem:** Write the expressions $2 \times 2^a$ and $4 \times 2^b$ as a single power of 2. 2. **Recall the rule for multiplying powers with the same base:** $$2^m \times 2^n = 2^{m+n}$$ 3. **Solve part (a):** Given $2 \times 2^a$, note that $2 = 2^1$. So, $$2 \times 2^a = 2^1 \times 2^a = 2^{1+a}$$ 4. **Solve part (b):** Given $4 \times 2^b$, note that $4 = 2^2$. So, $$4 \times 2^b = 2^2 \times 2^b = 2^{2+b}$$ **Final answers:** (a) $2^{1+a}$ (b) $2^{2+b}$