Respuesta :
The rationals being closed under subtraction means that if we start with two rational numbers and subtract them, we get another rational number. Choice c subtracts two rational numbers but gets the wrong answer, so isn't support for anything. Choice b is rational too because the square root of 4 is 2.
Answer: b
A rational number is said to be closed if the subtracted values and the result obtained are rational. Hence, the equations which supports the condition are :
- 5.5 - 0.5 = 4
- 5√4 - √4 = 4√4
Evaluating the options :
A.)
√8 - √8 = 0 ; the added values aren't rational and the result, Zero is not rational either.
B.)
5√4 - √4 = 4√4
5(2) - 2 = 2(2)
10 - 2 = 4
All the values in the expression are rational ; hence, it supports the assertion.
C)
5.5 - 0.5 = 4 ; all the values in the expression are rational, hence, it supports the fact.
2√3 - √3 = √3 ; the values in the expression are not rational, hence, it does not meet the condition.
Therefore, only options B and C supports the assertion.
Learn more : https://brainly.com/question/13644298