In the proof that the sum of rational numbers ab and cd , where a, b, c, and d are integers and b and d are non-zero, is a rational number, name the property that states that ad+bc and bd are integers. Enter 1 for option 1, 2 for option 2, and 3 for option 3.

Option 1: Associative Property

Option 2: Closure Property

Option 3: Commutative Property

9 answers

The property that states that \( ad + bc \) and \( bd \) are integers is the Closure Property. Therefore, the correct answer is:

2

Without solving, will the sum of 4.2+36−−√ be rational or irrational? Enter 1 for rational. Enter 2 for irrational. (1 point)

To determine if the sum \( 4.2 + \sqrt{36} \) is rational or irrational, we first note that \( \sqrt{36} = 6 \), which is a rational number. The number \( 4.2 \) is also rational.

The sum of two rational numbers is always rational. Therefore, \( 4.2 + \sqrt{36} = 4.2 + 6 \) will be rational.

The correct answer is:

1

What must be true about ab if cd and ad+bcbd are both rational numbers? Enter 1 for option 1 and 2 for option 2.

Option 1: ab is rational

Option 2: ab is irrational

(1 point)

If \( cd \) and \( \frac{ad + bc}{bd} \) are both rational numbers, then for \( ab \) to maintain the overall property of rationals, it must also be rational.

Thus, if \( cd \) is rational (which implies \( c \) and \( d \) are such that their product is a rational number) and \( \frac{ad + bc}{bd} \) is also rational (which involves the integers \( a, b, c, d \)), it directly follows that \( ab \) must also be rational.

Therefore, the correct answer is:

1

Without solving, will the product of 49−−√ and 13 be rational or irrational? Enter 1 for rational. Enter 2 for irrational.(1 point)

The product of \( \sqrt{49} \) and \( 13 \) can be determined as follows:

Since \( \sqrt{49} = 7 \), which is a rational number, and \( 13 \) is also a rational number, the product of two rational numbers is always rational.

Therefore, the product \( \sqrt{49} \times 13 = 7 \times 13 \) will be rational.

The correct answer is:

1

In the proof that the product of ab and cd , where a, b, c, and d are integers and b and d are non-zero, what does the Closure Property tell you about the products a⋅c and b⋅d ? Enter 1 for option 1 and 2 for option 2.

Option 1: They are both imaginary numbers.

Option 2: They are both integers.

(1 point)

The Closure Property states that the product of two integers is always an integer. Since \( a \), \( b \), \( c \), and \( d \) are all integers, the products \( a \cdot c \) and \( b \cdot d \) must also be integers.

Therefore, the correct answer is:

2