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Algebra Equations: Translation

Link of the Day

Today, I returned to History.com's "This Day in History" resource to see what kinds of things happened on the May 18ths of the past. On May 18, 1896, the Supreme Court issued an opinion on the landmark case Plessy v. Ferguson and dealt a major victory to supporters of racial segregation by supporting the legal standard of "separate but equal." Another quick online search brought me to this page from PBS with more details of the case, including the fact that Homer Plessy, a very light-complected man who was considered black because of his heritage, deliberately sat in the white car on a train in order to challenge Louisiana's Separate Car Act. 

5/18 Algebra Equations: Translation

Read the following SAT test question and then select the correct answer.

Always follow the Knowsys Method for math problems. It will save you time not only on the SAT, but also on math tests and quizzes in your school classes. Read the question carefully and identify the bottom line. Assess your options. Ask what you could do and then what you should do, and solve the problem quickly and efficiently once you have decided on a strategy. Finally, loop back to double check that you answered the question correctly.

First, 3 is subtracted from x and the square root of the difference is taken. Then, 5 is added to the result, giving a final result of 9. What is the value of x?

Wow! All those math terms close together are very effective at making this problem look scary. It is not really complicated, but when you come across problems like this (or ones like this) it is important not to let the test writers intimidate you. First, as always, look for the bottom line. At least that's easy to find:

x = ?

Next, assess your options. How could you approach this problem? On the test, of course, you could choose to skip this problem entirely, but I would not recommend it. Instead, you could try translating the problem from English sentences to a mathematical equation.

First, 3 is subtracted from x    So, 

and the square root of the difference is taken.    So,

Then, 5 is added to the result    So,

giving a final result of 9.    So,


Now you have a simple algebraic equation, and all you have to do is solve for x!


Start with    

Subtract 5 from both sides.    

Square both sides to remove the radical.    

Add 3 to both sides.    


Now, loop back to your bottom line. You were looking for the value of x, and you found x = 19, so that is the correct answer to the question! Check the answer choices.

A) 3

B) 4

C) 5

D) 16

E) 19

The answer is E.


On sat.collegeboard.org, 58% of responses were correct.


For more help with math, visit www.myknowsys.com!