In one sentence, describe what the following article is about: Solving a system of equations by addition is ideal when you see that both equations have one variable with the same coefficient with opposite charges. For example, if one equation has the variable 3x and the other has the variable -3x, then the addition method is ideal.  Write one equation above the other by matching up the x and y variables and the whole numbers. Write the addition sign outside the quantity of the second system of equations. Ex: If your two equations are 3x + 6y = 8 and x - 6y = 4, then you should write the first equation over the second, with the addition sign outside the quantity of the second system, showing that you'll be adding each of the terms in that equation.  3x + 6y = 8 +(x - 6y = 4) Now that you've lined up the two equations, all you have to do is add the like terms. You can take it one term at a time:  3x + x = 4x 6y + -6y = 0 8 + 4 = 12 When you combine it all together, you get your new product:  3x + 6y = 8 +(x - 6y = 4) = 4x + 0 = 12 Once you've eliminated one of the variables by getting a term of 0 when you subtract variables with the same coefficient, you should just solve for the remaining variable by solving a regular equation. You can remove the 0 from the equation since it won't change its value.  4x + 0 = 12 4x = 12 Divide 4x and 12 by 3 to get x = 3 Now that you know that x = 3, you just have to plug it into one of the original equations to solve for y. It doesn't matter which one you choose because the answer will be the same. If one of the equations looks more complicated than the other, just plug it into the easier equation.  Plug x = 3 into the equation x - 6y = 4 to solve for y. 3 - 6y = 4 -6y = 1 Divide -6y and 1 by -6 to get y = -1/6 You have solved the system of equations by addition. (x, y) = (3, -1/6) To make sure that you solved the system of equations correctly, you can just plug in your two answers to both equations to make sure that they work both times. Here's how to do it:  Plug (3, -1/6) in for (x, y) in the equation 3x + 6y = 8.  3(3) + 6(-1/6) = 8 9 - 1 = 8 8 = 8   Plug (3, -1/6) in for (x, y) in the equation x - 6y = 4.  3 - (6 * -1/6) =4 3 - - 1 = 4 3 + 1 = 4 4 = 4
Summary: Write one equation above the other. Add like terms. Solve for the remaining term. Plug the term back into the equation to find the value of the first term. Check your answer.

In one sentence, describe what the following article is about: Viewers (also called peepholes) allow you to see who is on the other side of the door. Install wide-angle viewers at eye level on all exterior doors. If you have to open your door to see, your locks won't do you much good. Try to find peepholes with covers to prevent people from looking back in with special tools, like a reverse peephole viewer.
Summary: Install viewers.

In one sentence, describe what the following article is about: One of the most efficient ways of improving your reading speed is to preview the material before you read it. This can help you to get a sense of what the text is about and allow you decide if it's even worth reading in full.  To preview the material, try reading the entire first paragraph, the first sentence of each successive paragraph and the entire last paragraph. In between these items, look at headings, bullet points and highlighted words. This won't give you all the details, but it will help you to identify the most important parts to go back to and what you can simply skim over. This is a good technique for long, unfamiliar or difficult texts which you are trying to get an initial grasp of. Another technique is to simply scan the material and pick out any key words. By using this method, you can develop a basic understanding of the material without wasting time on the nitty gritty. For example, in the sentence "the fearsome lion stealthily hunted its unsuspecting prey -- the antelope," it is not necessary to read every single word in order to grasp its meaning. By skimming the text for key words you can come up with the phrase "lion - hunted - antelope", which communicates essentially the same meaning. following this step allows you to halve the time it takes to read a text without sacrificing too much meaning. This technique is best used for simple, short texts, such as magazine and newspaper articles. If you're reading an article, book or paper for the sole purpose of gleaning new information, then a handy technique is just to read the first and last sentence of each paragraph, especially when it's reiterating something you already know.  A lot of non-fiction work can be very repetitive and contain long-winded explanations of a simple concept. If you already have a grasp of the concept, then there's no need to go through the entire paragraph line by line. This also goes for newspaper and magazine articles -- if you only want a basic overview of the contents, it's amazing how much information you can glean simply by reading the first and last sentence of each paragraph. If you're trying to improve your reading speed, you should get used to the idea of skipping over information you already know or understand, as reading these sections will provide you with little additional value.  You can decide which sections are worth reading by skimming the text for key words or reading the first sentence of each paragraph. This will give you a pretty good idea of what the text contains and allow you to decide whether its worth the time investment. This also goes for things that you're not interested in. If you're reading something like a memoir or historical account, it's fine to skip over the parts you're not interested in reading about. This may go against your nature as a reader, but it will save you time while also helping you to maintain interest in what you're ready. Related to this, you should not feel bad about abandoning a book that you're not enjoying or learning anything from. Many books are poorly written or don't do a good job of explaining advanced concepts. Try to read about 10% of every book you pick up and if you find it's not working for you put it down and move on to a different book. This will save you time and be more beneficial in the long run. One of the major issues people have when they begin to read faster is that they have difficulty absorbing and retaining the information they come across. While the major solution to this problem is to become a more active and engaged reader, there are several more specific techniques you can try.   Link concepts in the book to things you already know. Linking complex ideas to a personal experience, memory or emotion will help you to access the information more easily. As a simple example, linking the French word heureux (which means happy) to a pleasant memory where you experienced feelings of happiness might help you to remember the word more easily.  Highlight important information and write summaries. Use a highlighter while you're reading (or just dog-ear entire pages) to highlight important concepts or ideas. Then once you've finished the book, go back to these highlighted sections and use them to make a 200-300 word summary of the book. Doing this will provide you with a database of references that your can use in the future, which also helping you to commit the ideas to memory.
Summary:
Preview the material. Scan for the most important words. Read the first and last sentence of every paragraph. Skip over the parts you already know. Retain the most important information.