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
<span>–3cd – d(2c – 4) – 4d
= </span><span>–3cd – 2cd + 4d – 4d
= -5cd
answer
</span><span>A:–5cd </span>
Answer:
Kay made 8 phone calls
Stephanie made 13 phone calls
Explanation:
Assume the number of phone calls that Stephanie made is x.
We are given that:
Kay made 5 phone calls less than Stephanie.
This means that:
Kay made x-5 phone calls
We know that the total number of phones is 21.
This means that:
21 = x + x - 5
Now we solve for x as follows:
21 = x + x - 5
21 = 2x - 5
2x = 26
x = 26/2
x = 13
This means that:
Stephanie made x = 13 phone calls
Kay made x - 5 = 13 - 5 = 8 phone calls
Hope this helps :)
