Question

The perimeter of a rectangle billboard is 60 feet and has a length 6 feet longer than its width. Find the dimensions of the billboard.

Answer 1

$P=2l + 2w$

$l=6+w$
$60 = 2l+2w$

$60=2(6+w)+2w$
$60=12+2w+2w$
$60=12+4w$
$48=4w$
$12=w$

$l=6+(12)$
$l=18$

$length:18ft \\ width:12ft$

Answer 2

$x-width\\x+6-length\\\\2x+2(x+6)=60\\\\2x+2\cdot x+2\cdot6=60\\\\2x+2x+12=60\\\\4x+12=60\ \ \ \ /-12\\\\4x=48\ \ \ \ /:4\\\\x=12\ (ft.)\\\\x+6=12+6=18\ (ft.)\\\\Answer:18ft.\ \times\ 12ft.$