TITLE: Proofing this math pattern
QUESTION [0 upvotes]: I have this proof/pattern I am trying to solve:
2 + 3 = 8
3 + 7 = 27
4 + 5 = 32
5 + 8 = 60
6 + 7 = 72
7 + 8 = ?
I have to find what the question (?) represents, until now I have tried a few approaches but they are coming up with different answers, is there a fixed solution to this, if so, what is the most logical way using a proof? Appreciate all the insights for this problem....

REPLY [0 votes]: This one wasn't too bad: 
Notice: $$2 \times (3+1) = 8$$
$$3 \times (7+2) = 27 $$
$$4 \times (5+3) = 32$$
$$5 \times (8+4) = 60$$
$$6 \times (7+5) = 72$$
noticing that the second factor is $b+(a-1)$, we deduce that 
$$7 \times (8+6) = 98$$. 
The pattern is $a + b = a \times (b+a-1)$.

REPLY [0 votes]: First of all, I would advise you (or the question setter) to avoid using standard mathematical symbols and notation in a decidedly non-standard way.
Better to write something like $(x,y)$ yields $z$. 
Anyway your pattern seems to be: multiply both numbers together and add to the first number multiplied by its predecessor (one less). 
Example for $6$ and $7$: $6 \times 7 + (6)(6-1)=72$
So the last one is $98$
There may be other solutions. An infinite number of possibilities in fact.
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