Answer:
First, a rational number is defined as the quotient between two integer numbers, such that:
N = a/b
where a and b are integers.
Now, the axiom that we need to use is:
"The integers are closed under the multiplication".
this says that if we have two integers, x and y, their product is also an integer:
if x, y ∈ Z ⇒ x*y ∈ Z
So, if now we have two rational numbers:
a/b and c/d
where a, b, c, and d ∈ Z
then the product of those two can be written as:
(a/b)*(c/d) = (a*c)/(b*d)
And by the previous axiom, we know that a*c is an integer and b*d is also an integer, then:
(a*c)/(b*d)
is the quotient between two integers, then this is a rational number.
The answer to (1+_÷7+4)÷8= 4/7 is -3 I believe
answer: 105+3x
step by step: times 3 by 35 an then 3 times x
9) Because the total number of pencils is 180 and you will use them up in 30 days, the equation will have to equal 0 total pencils when 30 is substituted in for the time factor, or x. This already takes our choice 3 because it doesn’t meet this criteria.
The answer to how many pencils in 20 days could be answered by plugging in 20 for x. Choice 4 cannot work because it results in a negative number of pencils. Choices 1 and 2 use the same equation, so by plugging in 20 it is clear choice 2 is the correct answer.
10) A line parallel to the go en equation would have the same slope, -3, which means choices 1 and 4 are out. Plug in (-2,5) into both choices 2 and 3. Plugging -2 into x in choice 2 gives -5, and in choice 3 gives 5 for the y value. Therefore choice 3 is correct.
