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PLEASE HAVE OUT: u 1. PENCIL and PAPER (Possibly Eraser and Calculator) u 2. Yesterday’s HOMEWORK. PLEASE BE QUIET after the bell rings !
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Yesterday’s Homework Assignment -- Wednesday (10/7) u Pgs. 34-35: 10, 12, 14, 18, 22. u 10. Associative Property of Mltplctn u 12. Associative Property of Addition 14. Sample: 14 2 = 7, but 2 14 = 1 / 7 u 18. 2 u 22. $600
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Clear-Off-Desk except for: u PENCIL and PAPER! Possibly Eraser and Calculator Focus on Lesson!
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1.8 “The Distributive Property” Goal 1 - You will simplify expressions by applying the distributive property and justify the process used.
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In In Algebra Arithmetic Words Distributive Property a(b a(b + c) c) c) c) = ab ab +ac a(b a(b - c) c) c) c) = ab ab -ac 4(3 4(3 + 8) = 4(3) + 4(8) -8) = 4(3) -4(8) You You multiply the outside factor by the first inside term and then by the second inside term.
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u The Distributive Property is NOT very important in arithmetic. It just interesting to know. The Distributive Property is very important in Algebra. u It is vital to know! Distributive Property
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Distribute mean to spread over an area. Notice how the Distributive Property spreads a value over two or more terms. Distributive Property
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Example 1 – Using the Distributive Property A. A. Use the distributive property to write an equivalent numerical expression for the expression: 8(3 + 5). ä Solution ä 8(3 8(3 + 5) 5) = 8(3) 8(3) + 8(5)8(5)8(5)8(5)
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Example 1 – Using the Distributive Property B. B. Show that the two expressions in part A have the same value. 8(3 8(3 + 5) 5) = 8(3) 8(3) + 8(5)8(5)8(5)8(5) ä Solution ä 8(3 ä 8(3 + 5) 5) = 8(8) 8(8) = 64 ä 8(3) ä 8(3) + 8(5)= 8(5)= 24 + 40 = 64 ä The ä The expressions have the same value so they are equivalent.
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Equivalent Variable Expressions Equivalent Equivalent variable expressions expressions always have the same values when numbers are substituted for the variables. ä You ä You can use the distributive property to write equivalent variable expressions.
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Example 2 – Using the Distributive Property ä Write ä Write an equivalent expression. Then simplify. A. A. 2( x 2( x + 2) Solution 2( x 2( x + 2) = 2( x ) 2( x ) + 2(2) Distribute the the 2 = 2x 2x 2x 2x + 4 Simplify
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Write an equivalent expression. Then simplify. B. B. x(x x(x x(x x(x + 7) Solution x(x x(x x(x x(x + 7) = x ( x ) x ( x ) + x (7) x (7) Distribute the the x = x2 x2 x2 x2 + 7x 7x 7x 7x Simplify
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Write an equivalent expression. Then simplify. C. C. 2(3 x 2(3 x - 5) Solution 2(3 x 2(3 x - 5) = 2(3 x ) 2(3 x ) - 2(5) Distribute the the 2 = 6x 6x 6x 6x - 10 Simplify
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Write an equivalent expression. Then simplify. D. D. 5x 5x 5x 5x + 9x9x9x9x Solution 5x 5x 5x 5x + 9x 9x 9x 9x = (5 + 9) x 9) x Reverse Distribution = 14 x 14 x Simplify
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The Distributive Property ä The ä The distributive property also applies to sums with more than two variables. a(b a(b + c + d) d) d) d) = ab ab +ac +ad
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Example 3 – Using the Distributive Property Write Write an equivalent expression. Then simplify. 8(2 + 3 + 4) Solution 8(2 8(2 + 3 + 4) = 8(2) + 8(3) + 8(4) Distribute the the 8 = 16 + 24 + 32 Multiply = 72 72 Add
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1.8 “The Distributive Property” ä Are there any questions about The Distributive Property?
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1.8 “The Distributive Property” Goal 2 - You will use the distributive property to solve life-like problems. ä Use two methods to solve Example 4.
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Example 4 Applying the Distributive Property You are carpeting a bedroom and a closet. One square yard of carpet costs $20. What will the total cost be? Use two methods. 6 yd 3 yd 2 yd
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Example 4 Applying the Distributive Property Solution 1. 1. Find the total area of the room and closet. 6 yd 3 yd 2 yd
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Solution – Method A Think of the region as one large rectangle. A = lw = 6(3 +2) = 6(5) = 30 yd 2 6 yd 3 yd 2 yd
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Solution – Method B Think of the region as two smaller rectangles. A = 6(3) + 6(2) = 18 + 12 = 30 yd 2 6 yd 3 yd 2 yd
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Solution 2. 2. Multiply the cost for a square yard of carpeting by the number of square yards needed. 20 x 30 = 600 Answer: It will cost $600 to carpet the bedroom and the closet. 6 yd 3 yd 2 yd
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1.8 “The Distributive Property” ä Are there any questions about Applying the Distributive Property? ä Classwork ä 1.8 Pgs. 40-41: 1-20 and 44-45 ä SHOW STEPS!
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Make sure you have the proper heading and format. ä 930 Danny Dana 10 / 7 ä Math 7 - Dequer and 44-45 1. 8 Pg.40-41: 1-20 and 44-45 1. Please work Quietly and On-Your- Own for 15 min. SHOW STEPS ! You may now get help from and give help to near neighbors, etc.
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u 1. 3(2 + 7) = 3(2) + 3(7) = 6 + 21 = 27 3(2 + 7) = 3(9) = 27 u 2. 11(10 + 5) = 11(10) + 11(5) = 110 + 55 = 165 11(10 + 5) = 11(15) = 165 3. 17(8.5 - 1.5) = 17(8.5) - 17(1.5) = 144.5 - 25.5 = 119 17(8.5 - 1.5) = 17(7) = 119 1.8 “Guided Practice” Pgs. 40-41: 1-20 and 44-45
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4. 9(8 - 7) = 9(8) - 9(7) = 72 - 63 = 9 9(8 - 7) = 9(1) = 9 5. Incorrect ; 2(3 + 5) = 2(3) + 2(5) 6. Correct 7. Incorrect ; 6(4 x ) + 6(1) = 24 x + 6 8. Incorrect ; 2(3 a + 6) = = 6 a + 12 1.8 “Guided Practice” Pgs. 40-41: 1-20 and 44-45
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9. 4( x + 9) = 4( x ) + 4(9) = 4 x + 36 10. 3(5 x + 1) = 3(5 x ) + 3(1) = 15 x + 3 11. 8(4 - q ) = 8(4) - 8( q ) = 32 - 8 q 12. 2( x - 25) = 2( x ) - 2(25) = 2 x - 50 13. 32 a + 8 a = (32 + 8) a = 40 a 14. y (7) + y (9) = y (7 + 9) = 16 y 1.8 “Guided Practice” Pgs. 40-41: 1-20 and 44-45
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15. a ( b + 4 + c ) = ab + 4 a + ac 16. r ( s + t ) = rs + rt 17. 8(10) + 8(20) = 240 8(10 + 20) = 240 18. 40 19. 70 20. 100 44. D 45. H 1.8 “Guided Practice” Pgs. 40-41: 1-20 and 44-45
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Make-Up Tests Math 7 Make-Up Quizzes are still available TODAY, Thursday, (10/7/04), at 3:05 p.m. here in Room 29. ä If it is a retest bring the original Blue Scantron Form and colored quiz (if possible) with you.
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Class/Homework Assignment -- Thursday (10/7) u 1. Pgs. 40-41: 22, 24, 28, 32, 36, and 38. u Prove you’ve done the problems by SHOWING STEPS ! u Yes, you may continue your homework on the classwork paper.
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