# Algebra I 18ed by Armando Rojo PDF By Armando Rojo

ISBN-10: 950025204X

ISBN-13: 9789500252041

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For example, the interval notation ͑Ϫ3, 2͔ indicates the interval of all real numbers greater than Ϫ3 and less than or equal to 2. As on the graph of a set, the left parenthesis indicates that Ϫ3 is not included in the set. The right bracket indicates that 2 is included in the set. An interval is said to be a closed interval if it includes both endpoints; it is an open interval if it does not include either endpoint. An interval is a half-open interval if one endpoint is included and the other is not.

600. Rules for Addition of Real Numbers To add numbers with the same sign, add the absolute values of the numbers. Then attach the sign of the addends. To add numbers with different signs, find the absolute value of each number. Subtract the smaller of these two numbers from the larger. Then attach the sign of the number with the larger absolute value. HOW TO • 1 Add: a. Ϫ65 ϩ ͑Ϫ48͒ b. 27 ϩ ͑Ϫ53͒ a. Ϫ65 ϩ ͑Ϫ48͒ ෇ Ϫ113 • The signs are the same. Add the absolute values of the numbers. Then attach the sign of the addends.

0 1 2 3 4 5 1 2 3 4 5 0 1 2 3 4 5 0 1 2 3 4 5 1 2 3 4 5 ͕x͉1 Ͻ x Ͻ 3͖ −5 −4 −3 −2 −1 5 0 ͕x͉x Յ Ϫ2͖ −5 −4 −3 −2 −1 5 47. ͕x͉Ϫ1 Ͻ x Ͻ 5͖ −5 −4 −3 −2 −1 −5 −4 −3 −2 −1 5 45. 1 • Introduction to Real Numbers 15 For Exercises 51 to 58, write each set of real numbers in interval notation. 51. ͕x ͉ Ϫ2 Ͻ x Ͻ 4͖ 52. ͕x ͉ 0 Ͻ x Ͻ 3͖ 53. ͕x ͉ Ϫ1 Յ x Յ 5͖ 54. ͕x ͉ 0 Յ x Յ 3͖ 55. ͕x ͉ x Ͻ 1͖ 56. ͕x ͉ x Յ 6͖ 57. ͕x ͉ x Ն Ϫ2͖ 58. ͕x ͉ x Ն 3͖ For Exercises 59 to 68, write each interval in set-builder notation.