What is the smallest base-10 integer that can be represented as \(12_a\) in one base and \(21_b\) in another base, where a and b are any bases larger than 2?
1a + 2 = 2b + 1 I'll switch to use x and y
2y = x+1
y = 1/2x + 1/2
now solve for integers
when x = 3 y = 2 too small
when x = 5 y = 3
base 3 213 = 7
base 5 125 = 7 7