Fundamentals of Math

Fundamentals of Mathematics

5 − 2

3 + 4

=

⟹ 5( + 4 ) = 3( − 2 )

⟹ 5 + 20 = 3 − 6

⟹ 5 − 3 + 20 = 3 − 3 − 6

⟹ 2 + 20 − 20 = −6 − 20

2

−26 2

⟹ 2 = −26 ⟹

=

2

⟹ = −13

Practice 3.4.2

Directions: Solve for each unknown variable.

1. 3 + 2 = 2

2. 7 + 8 = 4 − 10

3. 5 + 15 = − 49

4. 5( + 4) = 6 − 5

+3 2

= +1 4

4 +6

= 3

5.

6.

−1

nswer Key on Page 120

3.5 Ratios and Proportions A ratio is a comparison of two (or more) quantities. The ratio of one number to another number is the quotient of the first number divided by the second number, where the second number is not zero. (A ratio is a fraction.) Ratios are most often written in fraction form (e.g., ), but can also be expressed in other forms such as : or .

Since a ratio can be written as a fraction, it can also be written in any form that is equivalent to that fraction. All of the following statements are equivalent:

10 50

1 5 , 1:5, 0.20, 20%, 1 out of 5

,

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