Question 329752
let width be x
length = 3x+12

Perimeter of rectangle  2*(L+W)
Perimeter of driveway = 2*(x+3x+12)
2*(4x+12)=168
8x+24=168
add -24 to both sides
8x+24-24=168-24
8x=144
x=144/8
x=18 feet the width
length = 3x+12
= 3*18+12
=66 feet the length