Question

find the length of rectangle if perimeter = 86cm and width = 18cm

Answer 1

Perimeter=86 cm
$perimeter \: = 2(l + b) \\ 86 = 2(l + 18) \\ 86 = 2l + 36 \\ 2l = 86 - 36 \\ 2l = 50 \\ l = \frac{50}{2} \\ l = 25cm$

Answer 2

perimeter of rectangle = 2(l+b)
perimeter= 86cm
width = 18cm
length= ?
perimeter = 2(l+b)
86=2(l+18)
86= 2l + 36
86-36 = 2l
50 = 2l
l = 50/2
so length = 25cm ans