How to Solve Equations with Negative Exponents

The Organic Chemistry Tutor

This video provides a step-by-step tutorial on solving an algebraic equation involving negative exponents ($x^{-2} + x^{-1} = 20$). The narrator begins by converting the negative exponents into rational expressions (fractions), transforming the problem into a rational equation. The solution process involves clearing the denominators to create a quadratic equation, rearranging it into standard form, and solving for $x$ using the factoring by grouping method. Key mathematical themes include the properties of exponents, specifically the rule $x^{-n} = 1/x^n$, solving rational equations by multiplying by the least common multiple, and factoring trinomials where the leading coefficient is not equal to one. The video also emphasizes the critical step of verifying solutions by substituting the answers back into the original equation to check for validity. For educators, this video serves as an excellent resource for Algebra 1 or Algebra 2 classes. It effectively bridges multiple concepts—exponent rules, rational expressions, and quadratic factoring—into a single problem. It can be used to demonstrate how algebraic structures can be disguised and how to manipulate equations into solvable forms. The clear, handwritten visual style makes it easy for students to follow the logical flow of the solution.