Question: which expression is equivalent to $42+70$ A:$6(7+10)$ B:$7(7+10)$ C:$14(3+5)$ D:$21(2+3)$
1. **State the problem:** We need to find which expression among A, B, C, and D is equivalent to $42+70$.
2. **Calculate the sum:**
$$42+70=112$$
3. **Evaluate each option:**
- A: $6(7+10)=6 \times 17=102$
- B: $7(7+10)=7 \times 17=119$
- C: $14(3+5)=14 \times 8=112$
- D: $21(2+3)=21 \times 5=105$
4. **Compare results:** Only option C equals $112$, which matches $42+70$.
5. **Conclusion:** The expression equivalent to $42+70$ is $14(3+5)$ (option C).