Let l represent length, and w represent width
l=3w-5
P=2(l+w)
46=2(l+w)
Divided 2 for both side
l+w=23
Now, I substitute l=3w-5 into this equation
3w-5+w=23
4w-5=23
Add 5 for both side
4w=28
Divided 4 for both side
w=7 inches
l=3w-5
l=3(7)-5
l=21-5
l=16 inches. As a result, the length is 16 inches, and the width is 7 inches. Hope it help!