Presentation on theme: "2.7 Division of Real Numbers 1 GOAL DIVIDING REAL NUMBERS VOCABULARY"— Presentation transcript:
12.7 Division of Real Numbers 1 GOAL DIVIDING REAL NUMBERS VOCABULARY reciprocalSince we use reciprocals when dividing, you must be able to write the reciprocal of a number. Remember:The reciprocal of the reciprocal ofSince 0 does not have a reciprocal, we cannot divide by 0.
2DIVISION RULETo divide a number a by a nonzero number b, multiply a by the reciprocal of b.EXAMPLE 1
42.7 Division of Real Numbers 2 GOAL WORKING WITH ALGEBRAIC EXPRESSIONS Since we divide by multiplying by the reciprocal, the same rules about signs apply.Rules for dividing two real numbers:If the signs are the same, the product is _______.If the signs are different, the product is ________.positivenegativeEXAMPLE 2
5Extra Example 2 Simplify the expression: Multiply by the reciprocal. Use the distributive property.Simplify.EXAMPLE 3
6Extra Example 3 Evaluate the expression when x = –5 and y = –1. a. b. c.Undefined
7Checkpoint 1. Simplify the expression –5d + 25 2. Evaluate the expression when s = –3 and t = –1.EXAMPLE 4
8Extra Example 4A mountain climber descends 300 feet in 50 minutes. What is her velocity?–300 feet=VelocityDisplacementTimeVERBAL MODELLABELSALGEBRAIC MODELSOLVEv50 minEXAMPLE 5
9Since 4x cannot equal 0, the domain is all real numbers except x = 0. Extra Example 5Find the domain of the functionSince 4x cannot equal 0, the domain is all real numbers except x = 0.
10Checkpoint1. An elevator descends 120 feet in 1.5 minutes. What is its velocity?2. Find the domain of the functionAll real numbers except x = –4.