Question

rezolvati ecuatia 
: xy+yx=77   x,y sunt cifre nenule in sistemul zecimal.

Answer 1

__  __
xy+yx=77
_________
x=?y=?
_________
__  __
xy+yx=77
10x+y+10y+x=77
11x+11y=77|:11
x+y=7
x∈{1,2...7}
y∈{1,2...7}