Page 88 - Math Course 1 (Book 1)

Dividing Rational Numbers

Divide by a Mixed Number REAL WORLD EXAMPLE
5
Find 3 3 ÷ 2 Write the product in simplest TRAVEL
form. 4 8
21 7 How many gallons of gas are
A. C. 2
25 10 needed to travel 78 3 miles if
4
1 miles per gallon?
a car gets 25
B. 1 3 D. 9 27 2
7 32
3 1
78
To f nd how many gallons, divide by 25
4 2
3 1 315 51 Write as improper
78 ÷ 25 = ÷
4 2 4 2 fractions

= 315 ÷ 2 Multiply by the
4 51 reciprocal of
51 2
2 51
Answer 105 1
315 2 Divide by common
=
2 4 17 51 factors.

MO. 2 - L7b = 105 or 3 3 Simplify.
34 34
Use Dimensional Analysis

to Divide Fractions 3 3 gallons of gas are
Answer
34 needed.

Let’s Begin Check Use dimensional analysis to examine
the units.

miles gallons Divide by
miles÷ =miles X
gallons miles common
Divide by an Algebraic Fraction units.

=gallons Simplify.
Examples The result is expressed as gallons.

5x 10 Your Turn!
Find ÷ Write the quotient in
8y 16y
simplest form. Divide by an Algebraic Fraction

5x 10 5x 16y Find 16m ÷ 9m
. Write the quotient in simplest
÷ =
8y 16y 8y 10 form. 10p 4
16y 10

Multiply by the multiplicative inverse of , 15p 27m²
10 16y A. C.
1 2 1 4 20p
= 5x 16y 4 24m
1 8y 1 10 2 B. D.
Divide by common factors. 15p 90mp

2x
Answer = or X Simplify.
2 Answer

80