Which equations support the fact that rational numbers are closed under addition?



Select each correct answer.

9√+9√=29√9+9=29

13+13=2313+13=23

6√+(−6√)=06+(−6)=0

2√+2√=22√

Respuesta :

Just took the test, the answer is; [tex] \sqrt 9 + \sqrt 9 = 2 \sqrt9              and \frac{1}{3} + \frac{1}{3} = \frac{2}{3} [/tex]

Answer: [tex]\sqrt{9} + \sqrt{9} = 2\sqrt{9}[/tex]

[tex]\frac{1}{3} + \frac{1}{3} = \frac{2}{3}[/tex]

Step-by-step explanation:

Since, according to the property that rational numbers are closed under addition.

If a and b are the rational number then (a+b) must be a rational number.

Since, In First option [tex]\sqrt{9} + \sqrt{9} = 2\sqrt{9}[/tex]

Addends √ 9 and √ 9 are rational number.

Also, 2 √9 is the rational number.

Thus It is following the property.

In Second option [tex]\frac{1}{3} + \frac{1}{3} = \frac{2}{3}[/tex]

Addends [tex]\frac{1}{3}[/tex] and [tex]\frac{1}{3}[/tex] are rational numbers.

Also, [tex]\frac{2}{3}[/tex] is a rational number.

Thus, It is also following the property.

Note: Both √6 and √2 are the irrational numbers.

This is why we did not take them.