"Solving Equations with the variable on each side." The first equation is 3k - 5 = 7k - 21. We are asked to "Solve each equation. Check your solution." The samples in her textbook are quite useless. Any ideas? Thank you.

Karen,

One thing to remember, always, is that **what you do to one side you
must do to the other**. That will be the key to success in these problems. Next,

**you want to solve for k**; therefore, your goal is to get the variable (in this case k) on one side alone, and the numbers on the other.

3k - 5 = 7k - 21

+5 +5 <- I am going to add 5 to get rid of it on the left side

3k = 7k - 16 <- negative 5 + positive 5 = 0, negative 21 + positive 5 = negative 16

So, you have the above equation and now you need the variable (k) on a side on its own

3k = 7k - 16

-7k -7k <- subtract 7k from both sides

-4k = -16 <- proceed to divide both sides by -4 and you end up with **
k=4**

Check: 3(4) - 5 = 7(4) - 21

12 - 5 = 28 - 21

7 = 7

Hope that made sense! Hard to explain math problems via answer box :)

## Comments

Hi Brittany,

Are you available this evening to assist my daughter with her homework? Thanks! Karen Henderson, Encino CA