How to Solve for X: 3x +2 = x - 10

Solve for x:    3x + 2 = x - 10
 
In this problem, there are three concepts that students need to learn:
 
First; collect like terms (variables & numbers)
Second; rule for adding, subtracting, dividing, and multiplying integers
Third; balancing equation using FAMILY REUNION strategy.
 
To solve for x:
  • First, student balances the equation using family reunion strategy which means numbers stay with numbers, variables stay with variables (letters).  Our ultimate goal is to make sure that the variable is by itself.  Equal sign is like the curtain. So, make sure you separate the numbers from the variable.  If you do anything on this side of the equal sign, make sure you do it on the side of the equal sign. This is when balancing equation comes in using family reunion meaning be with your own family or kind.
  • Second, collect like terms(either add or subtract) using integer rules
  • Solve for the answer
  • Prove it if answer is right or wrong by substituting answer to the variable (original problem).
    3x + 2 = x - 10
 
    3x - x = -10 - 2 (family reunion strategy, collecting like terms)
 
     2x =  -12  (Solve for X by dividing 2 to both sides, balancing equations, family reunion)
 
    2x/2 = -12/2
 
      x = -6
 
 
Proof:
 
     3x + 2 = x - 10
  
     3 ( -6) + 2 =  (-6) - 10
 
     -18 + 2 = -16
 
       -16 = -16 (balance) This tells us that X = -6 is true because both sides are balanced.
  • Subject : Math
  • Topic : Algebra 1, Algebra 2
  • Posted By : Admin
  • Created on : 10-10-2010

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