Question

Someone tell me, why and how is this operation. P=2(l+w)=2·(100+40)=280

Answer 1

The distributive property: a(b + c) = ab + ac

2 · (100 + 40) = 2 · 100 + 2 · 40 = 200 + 80 = 280

or calculate: 2 · (100 + 40) = 2 · 140 = 280

P = 2(l + w) - is perimeter of a rectangle /l-length, w-width/