VARIABLE SUBSTITUTION

SIMPLE

Concept: An equation is a mathematical statement that shows that two quantities are equal. When an equation contains a variable, we use algebra to find the value of the variable. To solve an equation means to find the number which replaces the variable to make the mathematical statement true. When the value of a variable is stated in the problem, simply substitute the value for the variable and complete the operation(s) in the equation.

Steps for Solving Variable Substitution Problems

Step 1 | Write the full equation.
Step 2 | Substitute values for variables when given.
Step 3 | Complete the operation(s) in the equation.
Step 4 | Write the final answer.

Example Solve the equation 17 / X= for C = 17.

Step 1 | Write the full equation. | 17 / X =
Step 2 | Substitute values for variables when given. (Remember that “17 / 17” is the same as “17÷ 17”) | 17 / 17 =
Step 3 | Complete the operation(s) in the equation. | 17 / 17 = 1
Step 4 | Write the final answer. | 1