Question 799038
sides l & w
l=5w-3 (1)
perim = 186 = 2*(l+w) (2)
subst for l
186=2*(5w-3+w) = 2*(6w-3) = 6*(2w-1) 
{{{ 186/6=2w-1 }}}
31+1=2w; w=16
l=80-3 = 77
sides 16cm and 77cm

Check: perim = 2*(16+77)=2*93=186