<PRE><B>Question 823403</B>
s = length of same length side
x = the third side
perimeter = 2s + x
x = s + 12    The wording is unclear so we might have x = 2s + 12
Substituting using s + 12 for s
perimeter = 2s + ( s + 12 )
perimeter = 3s + 12
Since perimeter is 84
      84 = 3s + 12
Subtract 12 from each side
      72 = 3s
Divide each side by 3
      24 = s
Since x = s + 12
      x = 24 + 12
      x = 36
The two same length sides are 24, and the third side is 36.</PRE>