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Learn how to simplify real number expressions using the laws of exponents and how to multiply and divide powers with the same base. Includes quizzes.
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Warm Up Problem of the Day Lesson Presentation Lesson Quizzes
Warm Up Evaluate. 27 1. 33 2. 4 • 4 • 4 • 4 256 3.b2 for b = 4 16 4. n2r for n = 3 and r = 2 18
Problem of the Day Calculate 6 to the fourth power minus 56. 1240
Sunshine State Standards Prep for MA.8.A.6.3 Simplify real number expressions using the laws of exponents. Also MA.8.A.6.4
The factors of a power, such as 74, can be grouped in different ways. Notice the relationship of the exponents in each product. 7 • 7 • 7 • 7 = 74 (7 • 7 • 7) • 7 = 73 • 71 = 74 (7 • 7) • (7 • 7) = 72 • 72 = 74
A. 66 •63 6 6+ 3 6 9 n 5 + 7 n 12 Additional Example 1: Multiplying Powers with the Same Base Multiply. Write the product as one power. Add exponents. B. n5 •n7 Add exponents.
1 2 Think: 2 = 2 5 + 1 2 6 24 4 + 4 24 8 Additional Example 1: Multiplying Powers with the Same Base Continued Multiply. Write the product as one power. C. 25 • 2 Add exponents. D.244• 244 Add exponents.
A. 42 •44 4 2 + 4 6 = 4 x 4 + 2 = x 6 Check It Out: Example 1 Multiply. Write the product as one power. 42• 44 = B. x4 •x2 x4•x2 =
1 + 2 2 + 2 15 p Check It Out: Example 1 Continued Multiply. Write the product as one power. C. 15• 152 151• 152 = = 153 D. p2• p2 p2•p2 = = p4
5555 5 5555 5 5 5 = = = 5 5 = 52 555 555 53 Notice what occurs when you divide powers with the same base.
5 7 3 7 5 – 3 7 2 7 10 x 9 x 10 – 9 x Think: x = x 1 Additional Example 2: Dividing Powers with the Same Base Divide. Write the quotient as one power. A. Subtract exponents. B. Subtract exponents. x
9 – 2 =9 8 – 5 3 = n = n Check It Out: Example 2 Divide. Write the quotient as one power. 9 9 A. 9 2 9 9 = 97 9 2 n 8 B. n 5 n 8 n 5
Reading Math 5 4 (9 ) is read as “nine to the fourth, to the fifth.” RAISING A POWER TO A POWER
Additional Example 3: Raising a Power to a Power Simplify. A. (54)2 (54)2 54 • 2 Multiply exponents. 58 B. (67)9 (67)9 Multiply exponents. 67 • 9 663
12 –3 2 3 12 • –3 2 3 Additional Example 3: Raising a Power to a Power Simplify. D. (172)–20 C. (172)–20 Multiply exponents. Multiply exponents. 172 • –20 17–40
Check It Out: Example 3 Simplify. A. (72)–1 (72)–1 1 72 • –1 = 7–2 = 49 B. (7–1)2 (7–1)2 1 7–1 • 2 = 7–2 = 49
4 4 –2 –2 1 5 1 5 –8 4 • –2 1 5 1 5 Check It Out: Example 3 Continued Simplify. D. (5–2)–3 C. (5–2)–3 = 5–2• –3 = 56 = = 15,625 = =58 = 390,625
Additional Example 4: Application The speed of sound at sea level is 3.4029 x 102 meters per second. A ship that is 5 kilometers offshore sounds its horn. About how many seconds will pass before a person standing on shore will hear the sound? Write your answer in scientific notation.
Additional Example 4 Continued distance = rate x time 5 km = (3.4029 x 102) x t Write 5 km as meters. 5000 = (3.4029 x 102) x t 5 x 103 = (3.4029 x 102) x t Write 5000 in scientific notation. 3.4029 x 102 3.4029 x 102 5 103 x = t 3.4029 x 102 102 1.469 x 101 t It would take about 1.5 x 101 seconds for the sound to reach the shore.
Check It Out: Example 4 The diameter of a red blood cell is about 7.6 × 10-4 millimeters. Thai has a slide with a 2-cm drop of red blood cells on it. Approximately how many cells are on the slide? Write your answer in scientific notation. (Hint: Find the ratio of the size of the drop, in millimeters, to the size of one cell.)
Check It Out: Example 4 Continued size of drop = number of red blood cells in drop; size of red blood cell 2 x 101 2 mm 2 cm = = 7.6 x 10–4 7.6 x 10–4 mm 7.6 x 10–4 mm 2 7.6 101 10–4 x = ≈ 0.2632 x 105 = 2.632 x 104 cells
Lesson Quizzes Standard Lesson Quiz Lesson Quiz for Student Response Systems
n 8 7 9 t9 109 4 t 2 10 t7 105 3 10 Lesson Quiz Write the product or quotient as one power. 1. n3n4 2. 8 • 88 4. 3. 6. (m2)19 m38 5. 32 • 33 • 35 8. (104)0 1 7. (9-8)9 9–72
Lesson Quiz for Student Response Systems 1. Write the product as one power. d4 d3 A. d7 B. d12 C. 7d D. 12d
Lesson Quiz for Student Response Systems 2. Write the product as one power. 44 43 42 A. 49 B. 414 C.424 D.4432
Lesson Quiz for Student Response Systems 3. Write the product as one power. (10–1)0 A. 10–10 B. 0 C.1 D.10