Answer:
The width is 18 feet and the length is 42 feet
Step-by-step explanation:
Let x feet be the width of the patio. The length of the patio is 6 feet longer than twice it’s width, then the length of the patio is 2x+6 feet.
Wayne is hanging a string of lights 78 feet long around the three sides of his patio, which is adjacent to his house. The side with length 2x+6 feet is adjacent to the house, so Wayne is hanging a string along three sides with lengths x ft, x ft and 2x+6 ft.
Hence,

The width
ft
The length
ft
The line crosses the x-axis at (0,4). The slope is also -1.
L=4+W
46=2L+2W
46=2(4+W)+2W
46=8+2W+2W
46=8+4W
38=4W
9.5=W
L=4+9.5
L=13.5 in.
Hope this helps. I can explain more if needed!!