Question

1+2 = 21
2+3 = 36
3+4 = 43
4+5 =? Please give me your best answer and your explanation for the answer.

Answer 1

The missing number(?) is 90.

Step-by-step explanation:

Given,

1 + 2 = $(1 + 2)^{2}$ + 12 = 9 + 12 = 21

2 + 3 = $(2 + 3)^{2}$ + 11 = 25 + 11 = 36

3 + 4 = $(3 + 4)^{2}$ + 10 = 49 + 110 = 59

Similarly,

?= 4 + 5 = $(4 + 5)^{2}$ + 9 = 81 + 9 = 90

Hence, the missing number(?) is 90.