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A=lw for l


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Jessica G. | Experienced SAT Prep and Math tutorExperienced SAT Prep and Math tutor
4.9 4.9 (110 lesson ratings) (110)
Hi Lauryn,
Here, you're looking to use your knowledge of inverse operations. That is, multiplication and division are inverses of one another, as are addition and subtraction. In the formula A=l*w, we utilize multiplication. In oder to solve for l, we need to use the inverse of multiplication to "cancel out" the w or "move it to the other side" of the equation. This is the same principle used when solving equations with numbers.
For example, when we ask what x stands for in the following equation, 15=5x, we use our knowledge of inverses to divide both sides of the equation by 5, thus giving 15/5=5x/5, or 3=x. The same principle is used in the problem your proposed, there just aren't any numbers to make it obvious!
Good luck!