Respuesta :
Answer:
(p-2l)/2 = b
Step-by-step explanation:
Formula for perimeter of a rectangle = 2(l + b)
We know,
perimeter = 80
length = 12
if we substitute the values -
p = 2 ( l + b )
p = 2l + 2b
(p-2l)/2 = b
(if you need the width : b = (p-2l)/2 = 80-24/2 = 56/2 = 28cm)