Answer:
ok so if we take length to be x we know width is x-3
the perimeter is the total length of sides, if you look at a rectangle you can see it has 4 sides with 2 length and 2 width. so perimeter is 2 times (x + x-3) = 26.
2x -3 = 13, 2x = 16, x = 8, 8 is length
the width is then 8-3 = 5.
Length = 8, width = 5.