Let length be L and let wide be W
L=4*W
L decreased 6 to form a side of a sqaure, then: L-6
and W increased 6 to form the other side of a square, W+6
In a square both sides would be equals, so: L-6=W+6 and we have before L=4W so replace this L and we get:
4W-6=W+6
Solve for W: 4W-W=6+6
3W=12
W=12/3=4
Now replace W into L=4W and we get L=4*4=16
Finally the dimensions for the rectangle are: Length=16 and Width=4
