Clarification on an answer

Understanding steps in a formula - There are certain points I do not understand in the answer an OTA gave me to a question I had asked yesterday, and I attach a document which sets out the original question and the points in the reasoning where I am having trouble.

Comparing Areas

Calculate AREA of Shape 1 then calculate the area of Re-arranged Shape 1. Did you get the same result? Why are they different? Please see the attached document.

Systems of Equations: Linear equation with 3 variables

1. 6x - y + 5z =47 2. -6x + 9y +4z = 10 3. -7x -6y + z = -91

Equation help

Solve for p where a=p(1+r)^t

Algebra: Solve for X

Solve for r where s=rl-a/r-1 Please show steps to solution.

Algebra: Solve for X

Please see the attached file for the full solution. Thanks for using BrainMass.

Algebra: Solve for X

Solve for a where s=n/2(2a+(n-1)d) Please show steps to solution

Algebra Problem of the week

There is a hallway that is infinitely long, with a series of lightbulbs that are all turned off. Someone enters and pulls the string on every light bulb, turning them all on. Another person enters, pulling the string on every other lightbulb. A third person enters, pulling the string on every third bulb. This continues indef ...continues

Complex Numbers: Solve the system of equations letting p=1/x and q=1/y.

Solve the following system of equations 4/x-9y=-1 -7x+6y=-3/2 HINT: let p=1/x and q=1/y

Systems of Equations : Substitute p and q for 1/x and 1/y

Please see the attached file for the fully formatted problems. Solve the following system of equations: 4/x - 9/y = -1 -7/x + 6/y = -3/2