Multiplying and Dividing Rational Numbers Lesson 2 3

Multiplying and Dividing Rational Numbers Lesson 2 -3 Algebra 1 Additional Examples Simplify each expression. 3 b. – 6( 4 ) a. – 3(– 11) = 33 The product of two negative numbers is positive. – 6( 3 ) = – 18 The product of a positive 4 4 number and a negative number is negative. 1 = – 4 2 Write – 18 as a 4 mixed number.

Multiplying and Dividing Rational Numbers Lesson 2 -3 Algebra 1 Additional Examples Evaluate 5 rs for r = – 18 and s = – 5. 5 rs = 5(– 18)(– 5) Substitute – 18 for r and – 5 for s. = – 90(– 5) 5(– 18) results in a negative number, – 90. = 450 – 90(– 5) results in a positive number, 450.

Multiplying and Dividing Rational Numbers Lesson 2 -3 Algebra 1 Additional Examples a Use the expression – 5. 5( 1000 ) to calculate the change in temperature for an increase in altitude a of 7200 ft. a – 5. 5( 1000 7200 ) = – 5. 5 ( 1000 ) Substitute 7200 for a. = – 5. 5(7. 2) Divide within parentheses. = – 39. 6°F Multiply. The change in temperature is – 39. 6°F.

Multiplying and Dividing Rational Numbers Lesson 2 -3 Algebra 1 Additional Examples Use the order of operations to simplify each expression. a. – 0. 24 = –(0. 2 • 0. 2) = – 0. 0016 b. (– 0. 2)4 = (– 0. 2)(– 0. 2) = 0. 0016 Write as repeated multiplication. Simplify.

Multiplying and Dividing Rational Numbers Lesson 2 -3 Algebra 1 Additional Examples Simplify each expression. a. 70 ÷ (– 5) = – 14 The quotient of a positive number and a negative number is negative. b. – 54 ÷ (– 9) = 6 The quotient of a negative number and a negative number is positive.

Multiplying and Dividing Rational Numbers Lesson 2 -3 Algebra 1 Additional Examples x Evaluate – y – 4 z 2 for x = 4, y = – 2, and z = – 4 – x – 4 z 2 = – 2 – 4(– 4)2 y – 4 Substitute 4 for x, – 2 for y, and – 4 for z. = – 2 – 4(16) Simplify the power. = 2 – 64 Divide and multiply. = – 62 Subtract.

Multiplying and Dividing Rational Numbers Lesson 2 -3 Algebra 1 Additional Examples Evaluate p 3 3 for p = and r = –. r 2 4 p =p÷r r Rewrite the equation. 3 (– 34 ) 3 4 = 2 ÷ = 2 (– 3 = – 2 ) 3 3 Substitute 2 for p and – 4 for r. 4 3 Multiply by – 3 , the reciprocal of – 4. Simplify.