Answer:
(D)x|x is a rational number.
Step-by-step explanation:
Given that:
The universal set, U is the set of rational numbers.
S is the set of integers.
Rational Numbers are numbers in the form , b≠0. They are denoted using ℚ.
The set of Integers on the other hand are the set of all positive and negative whole numbers inclusive of zero. They are denoted by ℝ.
Since the Universal Set is ℚ, the set S∈ℝ⊂ℚ (S is a Subset of the set of Rational Numbers). That is, every element in S is a rational number.
Therefore, every x in S is defined as:
x|x is a rational number.
The domain is the interval within which the values of x are meaningful/possible.
In the case of cost function, since we do not produce negative quantities of components, and there is no upper limit imposed on the production amount, the domain of the average cost function is therefore from zero to infinity (but excluding latter).
Written in interval notation, the domain is
Dom(C(x))=[0,infinity)
Ni : Zn: Cu = 7:2:9 =7x : 2x : 9x
7x+2x+9x = 3.8
18x=3.8
x=3.8/18=1.9/9≈0.21
Ni: 7x=7*0.21=1.47 ≈1.5 kg
Zn: 2x=2*0.21=0.42≈0.4 kg
Cu: 9x=9*0.21=1.89 ≈1.9 kg
Check 1.5+0.4+1.9 =3.8 True
Answer:
B.
The sum of 5 and 3 times the difference of a number and 6
5 + 3 x (X-6)
Hope this helps
Step-by-step explanation: