Question 201630
Let 

x = length of the first side, 
y = length of the second side, and
z = length of the third side



Since "the second side is one-third of the first side in length", this means that {{{y=(1/3)x}}}. Also, because "The third side is 2 meters less than the first side", we know that {{{z=x-2}}}



Recall that the perimeter "P" of ANY triangle with sides of "x", "y", and "z" is {{{P=x+y+z}}}



{{{P=x+y+z}}} Start with the given equation.



{{{26=x+(1/3)x+x-2}}} Plug in {{{P=26}}} (the given perimeter), {{{y=(1/3)x}}}, and {{{z=x-2}}}



So the algebraic equation is {{{26=x+(1/3)x+x-2}}}



If you wanted to find the lengths of the three sides, you would then solve for "x" (to eventually find "y" and "z"). Since the problem doesn't ask for it, I'll stop here. Let me know if you want to keep going.