Multiple Step Equations
Date: Wed, 7 Dec 1994 16:31:42 -0800 (PST) From: Phong Huynh Subject: Math Probs I am having problems with math problems like: 29 + q = -2(q - 13) and -2(c + 7) - 30 = 9c Please help. These are multiple step equations that I am having problems with.
Date: Wed, 7 Dec 1994 19:58:16 -0500 (EST) From: Dr. Sydney Subject: Re: Math Probs Hello there! Thanks for writing Dr. Math! We'd love to help you with your math problems. These can get a little tricky because it seems like there are lots of steps involved, but if we take it one step at a time, I think we can make sense of it. Okay, you are given an equation with an unknown, and you are asked to solve for the unknown. The general approach to problems like this is to get all the terms with the unknown on one side of the equals sign with the constants on the other side of the equals sign. Then you work with the equation until you have only the unknown on one side of the equals sign. Let's look at your problems, and try this strategy: First, what is q if 29 + q = -2(q - 13)? Our first step is to get all the terms with q's on one side of the equals sign with constants on the other side. But before we can do that, we have to simplify the right hand side of the equation. We need to distribute the -2. So simplifying the right hand side of the equation, we get: -2(q - 13) = -2q + 26 So, the equation becomes: 29 + q = -2q + 26 Now, we want all the terms that have a q in them on one side of the equals sign and all the constants on the other side. So, let's add 2q to both sides and subtract 29 from both sides. Then we have: 2q - 29 + 29 + q = -2q + 26 + 2q - 29 This reduces to: 3q = -3 Now we are almost done. We want to know what q is, so if we divide both sides of the equation by 3, we will get our answer: 3q/3 = -3/3 So, we have: q = -1 You can always check your answer by plugging in -1 to the original equation. So, check: is 29 - 1 equal to -2( -1 - 13)? Yes, it is, so we did everything right. Did that make sense to you? I guess the steps you should take are: 1) Simplify (distribute if necessary) 2) Put like terms with like terms (Put all the terms containing the unknown on one side of the equals sign with the constants on the other side) 3) Divide or do what you must to simplify 4) Check to make sure your answer makes sense I hope this helps. Maybe you could do the second example and write back with your answer. Please write back if you have any other questions. --Sydney
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994-2015 The Math Forum