Math Is Easy - Use Algebra To Solve Word Problem 1!

If 27 is subtracted from three times a certain number,the result is 18. Find the number. (Note 1)

If we let n represent the number to be found, thesentence If 27 is subtracted from three times a certain number, the resultis 18.can be translated into the following algebraic equation:

3n27 = 18

Solve this equation

3n27 = 18

+ 27= + 27 Add 27 to bothsides

3n + 0 =45

3n = 45

3n/3 = 45/3 Divideeach side by 3

n = 15

Now we substitute the solutionfor n into the original equation to see if it works.

3n 27 =18

3(15) 27 = 18

45 27 =18

18= 18

We must also see if the solution works in theoriginal problem statement.

If 27 is subtracted from three times a certain number,the result is 18.

If 27 is subtracted from three times a certain number(3X 15), the result is 18.

If 27 is subtracted from 45, the result is 18.

4527 = 18

We have just solved a first degree equation.

(Note1)

The source for the problem statement is:

Intermediate AlgebraFor College Students by Jerome E. Kaufman


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