Answer:
a. True. Rational numbers are closed under the sum operation, therefore, the sum of two rational numbers is always a rational number.
b. True. irrational numbers are closed under the sum operation, therefore, the sum of two irrationals numbers is always a irrational number.
c. True. The square of a real number is always a number greater than zero, and the sum of two numbers greater than zero is greater than zero.
d. True. The real numbers are closed under the product operation, then if a and b are reals numbers, the product ab is also a real number.
Step-by-step explanation:
20 possibilities based on this as a combination not a permutation, 6 nCr 3 = 20
777377737666267#773727363653626728’e
10^1 = .2
10^2 = 2.0
10^3 = 20.0
So, the answer is 3.
