Solving Two-Step Equations

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Back to Algebra I

Here's where we start using the nitty-gritty of the inverse operations procedures. If you haven't been to the last section (about one-step equations), then I recommend you read it over first before proceeding here.

SADMEP

Sadmep? What is sadmep? I've never heard of that before!

That may be true, but you probably have seen inverse operations. We use the achronym PEMDAS to help us remember the order of operations. SADMEP is nothing more than the order of operations, but backwards! When we have to solve equations, we have to do everything backwards and in the opposite order. I'll assume that you are real good at solving one-step equations. Then, let's see an example!

2x - 5 = 9

Sadmep tells us that we need to get rid of all the subtraction and addition (or the "SA") and then simplify before anything else. So, here's how we proceed:

2x - 5 + 5 = 9 + 5

2x = 14

Then we take care of the multiplication and division next:

2x ÷ 2 = 14 ÷ 2

x = 7

If we had any other steps to get through after this, we could finish up by clearing any exponents and parentheses, but that's for another lesson!