Binary Operations Jamb Mathematics Past Questions
Question 11
A binary operation \(\oplus\) defined on the set of real number is such that x\(\oplus\)y = xy/6 for all x, y ∈ R. Find the inverse of 20 under this operation when the identity element is 6
- A. 1/12
- B. 10/3
- C. 1/20
- D. 9/5
Question 12
A binary operation ⊕ on real numbers is defined by x⊕y = xy + x + y for any two real numbers x and y. The value of (\(-\frac{3}{4}\))⊕6 is
- A. 3/4
- B. -9/2
- C. 45/4
- D. -3/4
Question 13
A binary operation Δ is defined by aΔb = a + b + 1 for any numbers a and b. Find the inverse of the real number 7 under the operation Δ, if the identity element is -1
- A. -7
- B. -9
- C. 5
- D. 9
Question 14
A binary operation is defined on the set of positive integers is such xy = 2x-3y+2 for all positive integers x and y. The binary operation is?
- A. commutative and close on the set of positive integers
- B. neither commutative nor closed on the set of positive integers
- C. commutative but not closed on the set of positive integers
- D. not cummutative but closed on the set of positive integers
Question 15
A binary operation on the real set of numbers excluding -1 is such that for all m, n ∈ R, mΔn = m+n+mn. Find the identity element of the operation.
- A. 1
- B. zero
- C. -1/2
- D. -1
