X * (x + 1) * (x -4) = 84
x^2 + x * (x -4) = 84
x^3 + x^2 -4x^2 -4x = 84
x^3 - 3x^2 -4x -84 = 0
Using the cubic equation calculator:
http://www.1728.org/cubic.htm
x = 6
width 6
length 7
height 2
.25 for each egg because $1:12 eggs means 1/12 = .25/3
4x+2=19
Step 1. Subtracting 2 from both sides,
4x+2-2=19-2
4x=17
Step 2. Dividing 4 from both sides,
x=17/4