How do I Use Guess & Check to Solve Equations?

Guess and check to solve equations.

Math has been around for thousands of years. In that time many different ways of solving equations have come about. One of the simplest and most basic ways of solving an equation is the guess and check method. To perform the guess and check method all you need is an unsolved equation and a guessed number.

Things You'll Need

• Equation

Instructions

1. Guess a number to replace the missing variable with. For example, in the equation

   2x + 1 = 3, we will guess x=2.

2. Insert the guessed number into the equation.

   Example:

   2(2) + 1 = 3

3. Solve the equation.

   Example:

   2(2) + 1 = 3

   4 + 1 = 3

   5 = 3

   x is not equal to 2 since 5 is not equal to 3.

4. Guess a new variable if you are incorrect as in the above example.

   Example:

   2x + 1 = 3

   x = 1

5. Insert the new number into the equation.

   Example:

   2(1) + 1 = 3

6. Solve the equation.

   Example:

   2(1) + 1 = 3

   2 + 1 = 3

   3 = 3

   The guess of x = 1 is correct since the equation solves to 3 = 3.

7. Continue to guess new variables if you have not gotten a correct answer.

Tips & Warnings

• Always double check your work.

References

• Differential Equations: Guess and Check
• SOS Math: Solving Equations