Section 3.5 solv eqnvarbothside (algebra)

Section 3.5 solv eqnvarbothside (algebra)

• 1.
  Section 3.5 Solving Equations with the variable on each side
• 2.
  1. solveequations with variables on both sides. 2. solve equations containing grouping symbols. Objectives The student will be able to:
• 3.
  1) Solve. 3x+ 2 = 4x - 1 You need to get the variables on one side of the equation. It does not matter which variable you move. Try to move the one that will keep your variable positive .
• 4.
  1) Solve3x + 2 = 4x - 1 Draw “the river” Subtract 3x from both sides Simplify Add 1 to both sides Simplify Check your answer - 3x - 3x 2 = x - 1 + 1 + 1 3 = x 3( 3 ) + 2 = 4( 3 ) - 1 9 + 2 = 12 - 1
• 5.
  2) Solve8y - 9 = -3y + 2 Draw “the river” Add 3y to both sides Simplify Add 9 to both sides Simplify Divide both sides by 11 Simplify Check your answer + 3y + 3y 11y – 9 = 2 + 9 + 9 11y = 11 11 11 y = 1 8( 1 ) - 9 = -3( 1 ) + 2
• 6.
  -3 3 Whatis the value of x if 3 - 4x = 18 + x? Answer Now
• 7.
  3) Solve4 = 7x - 3x 4 = 4x 4 4 1 = x 4 = 7( 1 ) - 3( 1 ) Draw “the river” – Notice the variables are on the same side! Combine like terms Divide both sides by 4 Simplify Check your answer
• 8.
  4) Solve -7(x - 3) = -7 -7x + 21 = -7 - 21 - 21 -7x = -28 -7 -7 x = 4 -7( 4 - 3) = -7 -7(1) = -7 Draw “the river” Distribute Subtract 21 from both sides Simplify Divide both sides by -7 Simplify Check your answer
• 9.
  What is thevalue of x if 3(x + 4) = 2(x - 1)? -14 -13 13 14 Answer Now
• 10.
  5) SolveDraw “the river” Clear the fraction – multiply each term by the LCD Simplify Add 6x to both sides Simplify Add 10 to both sides Simplify Divide both sides by 36 Simplify Check your answer 8 - 6 x = 30 x – 10 + 6x +6x 8 = 36 x – 10 + 10 + 10 18 = 36 x 36 36 1/2 = x 8 _ 3 x = 6 x - 1 10 5 2 (10) 8 _ (10) 3 x = (10) 6 x _ (10) 1 10 5 2
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  5) SolveDraw “the river” Clear the fraction – multiply each term by the LCD Simplify Add 2x to both sides Simplify Add 6 to both sides Simplify Divide both sides by 6 Simplify Check your answer 3 - 2x = 4x – 6 + 2x +2x 3 = 6x – 6 + 6 + 6 9 = 6x 6 6 or 1.5 = x
• 12.
  Special Case #1 6) 2x + 5 = 2x - 3 -2x -2x 5 = -3 This is never true! No solutions! Draw “the river” Subtract 2x from both sides Simplify
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  Special Case #2 7) 3(x + 1) - 5 = 3x - 2 3x + 3 – 5 = 3x - 2 3x - 2 = 3x – 2 -3x -3x -2 = -2 This is always true! Infinite solutions or identity Draw “the river” Distribute Combine like terms Subtract 3x from both sides Simplify
• 14.
  What is thevalue of x if -3 + 12x = 12x - 3? 0 4 No solutions Infinite solutions Answer Now
• 15.
  Challenge! What isthe value of x if -8(x + 1) + 3(x - 2) = -3x + 2? -8 -2 2 8 Answer Now
• 16.
  Classwork / HomeworkPage 152 # 16 - 34