Question 1195807
The number 35 has the property that when its digits are both increased by 2, and then multiplied, the result is 5 times 7=35, equal to the original number.
Find the sum of all two-digit number such that when you increase both digits by 2, and then multiply these numbers, the product is equal to the original number.
:
Two digits y & x, the number 10y+x
(y+2) * (x+2) = 10y + x
xy + 2y + 2x + 4 = 10y + x
rewrite this and combine
10y - 2y + x - 2x - xy  = 4
8y - x - xy = 4
8y - xy = x + 4
y(8-x) = x + 4
y = {{{(x+4)/(8-x)}}}
In your graphing calc table, the only single digit integers:
 x  y
2 | 1, which is: 4*3=12
4 | 2, 6*4=24
5 | 3, 7*5=35
6 | 5, 8*7=56
:
The sum of all these two digit numbers
12 + 24 + 35 + 56 = 127