Getting One Solution - A Linear Equation

By Susan LoFranco on Apr 24, 2017

Student will solve simple algebraic equations with one variable using addition and subtraction

  • Understand the properites of operations to generate equivalent expessions, identifying when two expressions are equivalent
  • Nemeth: Parentheses, fraction indicators

Materials

If a computer is available further practice can be found at http://www.ixl.com/math/grade-8

 

Procedure

  • Review Vocabulary: equation, variable (some number) 
  • With student discuss how when they were in lower grades teachers often gave them a problem such as ? + 3 = 5.  Remind the student that they were able to solve this quickly once they understood their addition facts so that the answer would be 2 + 3 = 5. Solving an equation is somewhat similar but the solution will be more advanced.  In general to solve an equation you must "undo" whatever has been done to the variable.  Let's look at the problem x + 6 = 14.  This is a wonderful opportunity to instill in the student the need to keep track of all the steps in solving the problem.  Explain that whatever is done to one side of the equation must be done to the other side of the equation. Formatting the work as follows is the important

x + 6 = 14 

    - 6 = -6

__________

x       = 8

  •  Although a student may be able to solve the problem in their head try to enforce the documentation.  It is an important skill as the student progresses. 
  • If this is clear to the student try the next problem, x + 6 = -3

Solution 

x   + 6 = -3

       -6 = -6

_________

x         = -9

  • Try one more problem with the student x - 3 = 5
  • Once the student is confident, to reinforce the lesson, have the student complete the attached One Step Equations worksheet using the students media of choice to record his/her responses. 

One step equations worksheet

linear equation collage

 

Variations

Formatting the work is very important.  As the student progresses through Algebra and solving more complicated problems it is essential that they are organized and can retrace steps taken in solving the problem.  If you spend added time on formatting it is well worth it for the future.