Solving Two Step Equations

Solving Two-Step Equations:
* Ask yourself:
"Is there the distributive property?"
"What are the operations on each side?"
"Can I combine like terms ON THE SAME SIDE of the equation?"
"What are the inverse operations I need to do?"
"How do I get the variable to one side?"

Example:
4a + 3 - a = -7 + 2 + a

* combine like terms on each side of the equation:
3a + 3 = -5 + a

* subtract 3 from both sides
3a = -8 + a

* subtract a from both sides
2a = -8

* divide both sides by 2
a = -4

Check:
4(-4) +3-(-4) = -7 + 2 + (-4)
-16 + 3-(-4) = -5 + (-4)
-13-(-4) = -9
-9=-9

You're turn! Try this:

18 = 3(2k +1) - k

(Answer: 

k = the number of days in the week minus the days that start with S and T)