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Lesson 1-1 Expressions and Formulas
Step 1. Evaluate expressions inside grouping symbols Step 2. Evaluate all powers Step 3. Do all multiplication and division from left to right Step 4. Do all addition and subtraction from left to right
Examples
Find the value of 8 – 2{20 ÷ [1 + (3)2]}. 8 – 2{20 ÷ [1 + (3)2]} = 8 – 2[20 ÷ (1 + 9)] First square 3. = 8 – 2(20 ÷ 10) Then add 1 and 9. = 8 – 2(2) Divide 20 by 10. = 8 – 4 Multiply 2 by 2. = 4 Finally, subtract 4 from 8. Evaluate a3 + b(c – 1)2 – c2 if a = –2, b = 2.5, and c = 3. a3 + b(c – 1)2 – c2 = (–2)3 + 2.5(3 – 1)2 – 32 Replace a with –2, b with 2.5, and c with 3. = –8 + 2.5(3 – 1)2 – 32 Find (–2)3. = –8 + 2.5(2)2 – 32 Subtract 1 from 3. = –8 + 2.5(4) – 9 Find 22 and 32. = –8 + 10 – 9 Multiply 2.5 and 4. = –7 Do all additions and subtractions from left to right. The value is –7. Evaluate n2 – 5ap 6 – p2 if a = 5, n = –2, and p = –1. The fraction bar acts as both an operation symbol, indicating division, and as a grouping symbol. Evaluate the expressions in the numerator and denominator separately before dividing. n2 – 5ap 6 – p2 = (–2)2 – 5(5)(–1) 6 – (–1)2 a = 5, n = –2, and p = –1 = 4 – 5(–5) 6 – 1 Evaluate the numerator and the denominator separately. = 4 – (–25) 6 – 1 Multiply 5 and –5 in the numerator. = 29 5 or 5 4 5 Simplify the numerator and the denominator. Then divide. The value is 5 4 5 .
Practice
1. Find the value of 5 + 22 - 8 + 3. 2. What is the value of 9 - [12 + (15 ÷ 3)]? 3. Evaluate a - b2 if a = 4 and b = 3. 4. The formula for the perimeter of a rectangle is , where is the length of the rectangle and w is the width. If a rectangle is 17 ft long and 8 ft wide, what is its perimeter? 5. Evaluate if a = 2, b = 4, and c = -1.
Test
Evaluate z – (2yz + y) · y if y = -3 and z = 2. A. 9 B. 23 C. -43 D. 47 The formula for the perimeter of a rectangle is , where is the length of the rectangle and w is the width. If a rectangle is 17 ft long and 8 ft wide, what is its perimeter? A. 25 ft B. 42 ft C. 68 ft D. 50 ft Evaluate if a = 2, b = 4, and c = -1. A. 1 B. 2.4 C. 7 D. -14 Evaluate p · (p + 3q) – r if p = -7, q = 4, and r = -16. A. 77 B. 45 C. -19 D. -51 Find the value of 5 + 22 - 8 + 3. A. 4 B. 2 C. -4 D. -2
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