How to Find the X Factor in a Math Equation

By Carol Taber
Solving for X is the building block for understanding algebra.
letter x image by MLProject from Fotolia.com

According to the All Math website, algebra is the area of math "dealing in representing numbers with letters." Understanding algebra is the basis for learning and applying higher-level math such as calculus and physics. Algebra is on both the SAT and GED tests. Occupations that require a mastery of algebra include electronics, engineering, computer science, medical research and analysts. All algebra concepts build in this basic mathematical linear equation: X + A = B, where A and B are known quantities.

Rewrite the equation using the given numbers for A and B. For this example, the equation is X + A = B, where A= 5 and B = 9. Rewritten, the equation is X + 5 = 9. X in this equation is known as the variable.

Subtract the same amount from each side of the equation so that X (the variable) is on one side of the equation and the known numbers are on the other side.

For our example: X + 5 - 5 = 9 - 5. Working the math, the equation now reads X = 4.

Replace X with your answer in the original algebraic equation to see if the solution is correct. X + 5 = 9, where X = 4 is rewritten 4 + 5 = 9. Because 4 + 5 does equal 9, you can be sure you found the correct X factor for this equation.

About the Author

Based in North Carolina, Carol Taber has been writing since 2008. Her work is published on her blog, A Second Cup, and on various other websites. She is currently a features writer for The Wake Weekly and holds a Bachelor of Arts in accounting from the University of New York at Buffalo.