How to Math Equations with 3 or 4 Variables

Learn to identify and solve exponent problems with 3 or 4 variables, problems which frequently appear on the PSAT, SAT, ACT, and other standardized tests.

Difficulty: Moderately Challenging

Instructions

Things You'll Need:

• brain
• pencil
• calculator

1. APPROACH FOR SAT MATH EQUATIONS WITH 3 OR 4 VARIABLES
   
   Equations with 3 or 4 variables appear frequently in the last part of Math sections of standardized tests.
   
   Do not get scared or confused by the vast number of variables, but instead approach these equations exactly as you would an equation that contains only one variable.

2. When faced with these questions, make sure to first identify the final form of your answer.
   
   This form will not only determine the easiest way to manipulate and solve the equation but it will also ensure that you don't get confused by the multiple variables in the problem.
   
   Example: If w - 7(d + 3) = p, what is the value of w in terms of d and p?
   
   The Final Form of Your Answer: w = ?dp

3. SAMPLE PRACTICE QUESTION FOR EQUATIONS WITH 3 OR 4 VARIABLES
   
   If js + j-1 = k - 2s + j/k , what is the value of s when j = 2 and k = .5?

4. Solution
   
   js + j-1 = k - 2s + j / k
   2s + 2-1 = .5 - 2s + 2/.5
   2s +1/2 = .5 - 2s + 4
   4s + 1/2 = 4.5
   4s = 4
   s = 1

Resources

• More Math Practice with Equations with 3 or 4 Variables