Rectangles a and b have the same perimeter but are different shapes rectangle s is 5 inches long and 3 inches wide. rectangle b is 6 inches longer than it is wide. what are the lenght and width of rectangle b ?

We know that
perimeter rectangle A=2*[5+3]> 16 in

let
x> length side rectangle B
y> width  side rectangle B
so
x=6+y> equation 1
16=2[x+y]> equation 2
I substitute 1 in 2
16=2*[6+y+y]> 16=2*[6+2y]> 16=12+4y> 4y=16-12
y=4/4> y=1 in
x=6+1>x=7 in

the answer is
the dimensions of rectangle B are
length side is 7 in
width  side is 1 in