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Bell Ringer Solve the following: 1. ) 7(4 – t) = -84 2
Bell Ringer Solve the following: 1.) 7(4 – t) = ) 78 = 3c +12 – c + 4 Go over homework from yesterday Pg even
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6-4 Solving Equations with the Variable on Both Sides
Objectives: to solve equations with the variable on both sides. to solve equations containing grouping symbols.
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To solve for a variable the variable must be positive with no number beside it!!
x = 10 Solved - x = -5 Not solved 2x = 5 Not solved -3x =6 Not solved Bottom page of notes
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To solve these equations,
Use the addition or subtraction property to move all terms from one side of the equal sign to another. 6x - 3 = 2x + 13 -2x x 4x - 3 = 13 Use the multiplication or division to bust a term up. (Separate the coefficient (number) from the variable (letter)) 4x = 16 x = 4
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Let’s see a few examples:
Make variable on 1 side of equation (do it so the variable is positive) 1) 6x - 3 = 2x x -2x 4x - 3 = x = x = 4 Be sure to check your answer! 6(4) - 3 = 2(4) = = 21
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Let’s try another! Check: 3(1.5) + 1 = 7(1.5) = = 5.5 2) 3n + 1 = 7n n -3n 1 = 4n = 4n 4 4 Reduce! 3 = n 2 Rewrite as n = 3/2
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Here’s a tricky one! 3) 5 + 2(y + 4) = 5(y - 3) + 10
Distribute first. 5 + 2y + 8 = 5y Next, combine like terms. 2y + 13 = 5y - 5 Now solve. (Subtract 2y.) 13 = 3y (Add 5.) 18 = 3y (Divide by 3.) 6 = y Rewrite as y = 6 Check: 5 + 2(6 + 4) = 5(6 - 3) (10) = 5(3) = = 25
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Let’s try one with fractions!
Steps: Multiply each term by the least common denominator (8) to eliminate fractions. Solve for x. Add 2x. Add 6. Divide by 6. 3 - 2x = 4x = 6x = 6x so x = 3/2 2 * 1 * 2 * 4 *
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(Notice there’s no variable at all in both cases.)
Two special cases: 6(4 + y) - 3 = 4(y - 3) + 2y y - 3 = 4y y y = 6y y - 6y 21 = -12 Never true! 21 ≠ -12 Write ………. NO SOLUTION! 3(a + 1) - 5 = 3a - 2 3a = 3a - 2 3a - 2 = 3a a -3a -2 = -2 Always true! We write IDENTITY. (Notice there’s no variable at all in both cases.)
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Try a few on your own: 9x + 7 = 3x - 5 8 - 2(y + 1) = -3y + 1
8 - 1 z = 1 z - 7
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The answers: x = -2 y = -5 z = 20
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Page , and 24 even Show your steps
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