P = 2(L + W)
P = 400
L = W + 40
400 = 2(W + 40 + W)
400 = 2(2W + 40)
400 = 4W + 80
400 - 80 = 4W
320 = 4W
320/4 = W
80 = W.....so the width (W) = 80 yards
L = W + 40
L = 80 + 40
L = 120...and the length (L) = 120 yards
Expanding the limit, we get (x^2+2x∆x+∆x^2-2x-2∆x+1-x^2+2x-1)/<span>∆x
Crossing the 1s , the 2xs, and the x^2s out, we get
(2x</span>∆x+∆x^2-2∆x)/<span>∆x
Dividing the </span><span>∆x, we get
2x+</span><span>∆x-2.
Making the limit of </span><span>∆x=0, we get 2x-2.</span>
28. Each person will get 2 pieces. 1/6=2/12
29. Each teacher will get 9 cookies. 1/4=(sorry, I'm not sure)
30. Each student will get 4 slices.1/16=4/64
31. She has made five.
Hope this helped :)
