Expert: Josh - 7/12/2007

Question
Solve each of the following for the variable y.

1. 3y = ab    

Answer:


Show your work:


2. ab= cy    

Answer:


Show your work:


3. ayc = bx    

Answer:


Show your work:


4.bx/y = R    

Answer:


Show your work:




5. zy/x = b    

Answer:


Show your work:


Answer
Mike,

You need to try this yourself to gain any benefit from it. Ultimately, you will be the person sitting for the exam, not me. If you don't know how to go about doing this, or if you don't see the point of the question, then please ask.

Main thing here is that we want to separate an unknown quantity (a variable called "y") from the rest of the equation. An equation in algebra is all about expressing some unknown quantity in terms of what we know (other variables).

o What are we allowed to do?
 In order to extract the variable "y" leaving it on one side of the equation, we carry out addition (or subtraction) and/or multiplication (or division) simultaneously on both sides of the equation.

In Q1, we divide both sides by 3 to get y=(ab)/3.

In Q2, we divide both sides by "c" to get (ab)/c=y. Usually, we write this as y=(ab)/c.

In Q3, we divide both sides by the product "a*c", this gives y=(bx)/(ac)

In Q4, we do this in two steps.
Step 1: multiply both sides by y
(bx)/y = R   becomes (bx) = Ry
Step 2: divide both sides by R,
(bx) = Ry   becomes y=(bx)/R

I'll let you try Q5.
Hint: To eliminate the x in the denominator, we need to multiply both sides by "x". Then, to get rid of the y, we need to divide both sides by "y". Good luck