if the length of a rectangle is increased by 40% and its width is decreased by 40% what is the effect on the rectangles area?

The area is multiplied by 0.84 (decreased 16%)

Step-by-step explanation:

The length is multiplied by (1 + 0.40) = 1.4.

The width is multiplied by (1 - 0.40) = 0.6

So, the new area is ...

A = (L·1.4) · (W·0.6) = LW·0.84

The original area was the product of the original length and width, so was LW. This means the new area is 0.84 times the original area.

0.84 = 1 - 0.16

so, another way to describe the change is to say the area decreased 16%.