Algebra help please show work and explain?

ok here it goes. lets say length is l and width is w. we know that l-4=w and that 2(l+w) is the formula for peremeter. so lets use guess and check stradegy since thats easiest to expalin to u online. lets say the length is 10. 10-4 is 6. if perimeter is 2(l+w) then it wud b 2 times 16 cuz 10 plus 6 is 16. 16 times 2 is onl 32 so we will guess bigger. so wat we can do is this: we know that the two variables have to multiply times 2 to make 120. that means our two variables need to add up to 60. so lets do this: 32 -4 is 28. 28 plus 32 is 60. 60 times 2 is 120. There we have it! So the length is 32 ft and the width is 28ft. hope i helped!!!!