.
The perimeter of a hexagon is 18x+5. Four sides have the following side lengths: 8x, 3x-2, x+3, 2x-3.
Choose all the pairs that could be the missing two sides.
a. 4x+2, x+5 <--- bad
b. 2x, 2x+7 <--- good
c. 5x-3, x+10 <--- bad
d. 3x-10, x+17 <--- good
The method:
Note that 8x + (3x-2) + (x+3) + (2x-3) = 14x - 2.
Thus two other addends should comlement 14x-2 to 18x+5.
It is easy to check that only options "b" and "d" satisfy this condition.