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Solving Equations Solutions

  • To solve an equation,    isolate    x (or other variable) on    one side    of the equal sign.

  • Whatever you do to one side of an equation, you    must    do on the other side to maintain    equality   .

    • You will do the    opposite    (inverse) operation to isolate the variable. For example:
      • 
If 2 is subtracted from x, you will    add    2 to both sides.
      • 
If 3 is multiplied by x, you will    divide    by 3 (or multiply by 13) on both sides.
      • 
With a fraction, if 45 is multiplied by x, you will divide by 45 which is the same as multiplying by the reciprocal    54   .

  • Remember to combine any    like terms    before solving.
    • 
Your final answer should have all fractions written in    simplest    form.

    • To check that your answer is correct,    substitute    the value of the variable back into the original equation.

In Algebra 1, you will learn how to clear fractions or decimals from an equation before solving.

Example 1

Solve.

27x+6=2

Plan

·27  ·72+6    6

Implement

27x+6=   26   67227x =42721x=14

Explain

  • Subtract 6 from both sides
  • Multiply by the reciprocal on both sides
  • Simplify the fraction

Check

2714+6=24+6=2 2=2 

Example 2

Solve.

85x+3=12

Plan

Distribute 85

   ·85   ·58+245245

Implement

85x+245=12 245   24585x=51048105885x=53102518x=5316

Explain

  • Distribute
  • Subtract
  • LCD(2, 5)=10
  • Multiply by the reciprocal

Check

855316+3=12855316+4816=1285516=12 

You can review how to make a problem-solving plan in the “Problem Solving” skills lesson.

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