Question 168875
Find all the two-digit whole numbers (greater than zero) such that the difference between the whole number and the product of its digits is 12
:
Let x = 10's digit
Let y = units digit
:
Write an equation for what it says:
:
(10x + y) - xy = 12
y - xy = 12 - 10x
y(1 - x) = 12 - 10x

y = {{{((12-10x))/((1-x))}}}
:
Use the equation, to find y
 x | y | no.|xy
---------------
 2 | 8 | 28, 16
 3 | 9 | 39, 27
and that's it