9514 1404 393
Answer:
5 + 8 = 45
Step-by-step explanation:
We observe that the sequence of numbers on the left is arithmetic, with each value increasing by 1 from each expression to the next.
Similarly, we observe that the sequence on the right increases by an increasing amount from one number to the next. First differences are 7, 9, suggesting that each successive line in the table will differ by 2 more than the previous two lines did.
Following this pattern, we have ...
4 + 7 = 32
5 + 8 = 45
_____
Additional comment
Here, it seems, the symbol "+" in the expression "a+b" is intended as a stand-in for the function f(a, b). That is, we're given three expressions ...
f(1, 4) = 5
f(2, 5) = 12
f(3, 6) = 21
and asked to predict the value of f(5, 8).
f may be any of a variety of functions. A couple of them are ...
f(x, y) = x^2 +4y -12
f(x, y) = y^2 -2x -9
or ...
f(n, n+3) = n(n+4), which could also be written f(x, y) = x(y+1)
