Article: As noted above, if the numerator and denominator of an expression share factors, these factors can be removed from the fraction entirely. Sometimes this will require factoring the numerator, denominator, or both (as was the case in the example problem above) while other times the shared factors are immediately apparent. Note that it is also possible to divide the numerator terms by the expression in the denominator individually to obtain a simplified expression. Let's tackle an example that doesn't necessarily require drawn-out factoring. For the fraction (5x2 + 10x + 20)/10, we may want to divide every term in the numerator by the 10 in the denominator to simplify, even though the "5" coefficient in 5x2 isn't bigger than 10 and thus can't have 10 as a factor. Doing so gets us ((5x2)/10) + x + 2. If we like, we may want to rewrite the first term as (1/2)x2 to get (1/2)x2 + x + 2. Expressions under a square root sign are called radical expressions. These can be simplified by identifying square factors (factors that are themselves squares of an integer) and performing the square root operation on these separately to remove them from under the square root sign. Let's tackle a simple example - √(90). If we think of the number 90 as the product of two of its factors, 9 and 10, we can take the square root of 9 to give the whole number 3 and remove this from the radical. In other words:  √(90) √(9 × 10) (√(9) × √(10)) 3 × √(10) 3√(10) Some algebraic expressions require multiplying or dividing exponential terms. Rather than computing each exponential term and multiplying or dividing manually, simply add exponents when multiplying and subtract when dividing to save time. This concept can also be used to simplify variable expressions.  For example, let's consider the expression 6x3 × 8x4 + (x17/x15). In each occasion where it's necessary to multiply or divide by exponents, we'll subtract or add the exponents, respectively, to quickly find a simplified term. See below:  6x3 × 8x4 + (x17/x15) (6 × 8)x3 + 4 + (x17 - 15) 48x7 + x2   For an explanation of why this works, see below:  Multiplying exponential terms is essentially like multiplying long strings of non-exponential terms. For example, since x3 = x × x × x and x 5 = x × x × x × x × x, x3 × x5 = (x × x × x) × (x × x × x × x × x), or x8. Similarly, dividing exponential terms is like dividing long strings of non-exponential terms. x5/x3 = (x × x × x × x × x)/(x × x × x). Since each term in the numerator can be canceled out by a matching term in the denominator, we're left with two x's in the numerator and none in the bottom, giving us an answer of x2
Question: What is a summary of what this article is about?
Simplify fractions by dividing through by common factors. Use square factors to simplify radicals. Add exponents when multiplying two exponential terms; subtract when dividing.
Article: If you have not yet done so, wash your face using your usual facial cleanser, then pat it dry with a soft, clean towel. You should never apply oil (or any type of moisturizer) to a dirty face. If you apply oil to a dirty face, you'll trap the dirt; this could lead to blackheads and breakouts. A little bit goes a long way, so you only need 2 to 4 drops. You can always apply more oil later, if necessary. This will help make it easier to absorb into your skin. It will also reduce the chances of you applying too much. Avoid rubbing the oil in. If you only want to use the oil to spot-treat a dry patch, pick the oil up from your palm with your ring finger, then gently pat your finger against your skin. This is especially important if you are treating the delicate skin under your eyes. If you have very dry skin, you could leave some of the excess oil on your skin. If your face feels too greasy, however, use a cotton pad to gently wipe off any residual oil.
Question: What is a summary of what this article is about?
Start with a clean face. Place a few drops of almond oil onto your palm. Rub your palms together to warm the oil up. Gently pat your hands against your face and neck. Wipe off any excess oil, if necessary.
Article: Benzoyl peroxide can help treat current acne while helping reduce the dark spots that remain afterwards. You can use benzoyl peroxide in cleansers, toners, gel, and topical spot treatments. Salicylic acid will help reduce the redness, size, and pores around acne blemishes. You can use it in your cleanser, toner, and other skincare products. It may even help prevent acne in the future. While this will not work for pink and red marks (which are due to irritation and not changes in melanin in the skin), for brownish marks you can use a skin lightener to reverse the hyperpigmentation. While somewhat declining in popularity, Hydroquinone remains a common chemical skin lightener which is available both over-the-counter and prescription-strength. You can use it twice daily for a set period of time (ask your doctor) to lighten specific spots.  It really should only take three treatments for skin lighteners to remove dark marks. Do not use these for too long or your skin may become permanently discolored gray.  Skin lightening products can increase your sensitivity to sun damage and cause premature aging. Always wear sunscreen when using these products, even on cloudy days.
Question: What is a summary of what this article is about?
Apply a product with benzoyl peroxide. Treat skin with salicylic acid. Use a skin-lightening serum for brownish marks. Use hydroquinone.