a binary operation ⊗ is defined by m⊗n=mn+m−n on the set of real numbers, for all m, n ∈  r. find the value of 3⊗(2⊗4)
a:  6   
b:  25 
c:  15 
d:  18
a binary operation ⊗ is defined by m⊗n=mn+m−n on the set of real numbers, for all m, n ∈  r. find the value of 3⊗(2⊗4)
a:  6   
b:  25 
c:  15 
d:  18
if m ⊗ n = mn + m - n,
(2 ⊗ 4) = (2x4) + 2 - 4
= 8 + 2 - 4
(2 ⊗ 4) = 6
(3 ⊗ 6) = (3x6) + 3 - 6
= 18 + 3 - 6
= 15
answer: c