Question

A rectangular garden's length is 5 feet longer than its width. If its perimeter can be represented using the function P(x) = 4x + 10, what is the width of the garden if its perimeter is 38 feet?

Answer 1

let
y----------> the length of the rectangle
x---------> the width of the rectangle
P--------> perimeter of a rectangle

we know that
P=38 ft
[P]=2*[x+y]------> 38=2*[x+y]------> equation 1
y=5+x-------> equation 2
substitute 2 in 1
P=2*[x+(5+x)]---------> P=4x+10---------> the given equation
4x=38-10--------> 4x=28----> x=7 ft
y=5+7-----> y=5+7------> y=12 ft

the answer is
the width is 7 ft