Question 3
The operator $\Delta$ gives $3\Delta2=15$, $4\Delta4=24$, $5\Delta9=42$, and $6\Delta1=21$. What is $2\Delta7$?
Pattern convention: use a simple common arithmetic rule consistent with all four examples; the examples alone do not determine a unique arbitrary operation.
Pattern convention: use a simple common arithmetic rule consistent with all four examples; the examples alone do not determine a unique arbitrary operation.