A binary operation \(\otimes\) is defined by \(m \otimes n = mn + m - n\) on the set of real numbers, for all m, n \(\in\) R. Find the value of 3 \(\otimes\) (2 \(\otimes\) 4).

  • A 6
  • B 25
  • C 15
  • D 18
jamb 2019mathematics

The correct answer is C. 15

To find the value of \(3 \otimes (2 \otimes 4)\), we'll follow the definition of the binary operation \(\otimes\).

Given:

\(m \otimes n = mn + m - n\)

Step 1: Evaluate \(2 \otimes 4\):

\(2 \otimes 4 = 2 \times 4 + 2 - 4 = 8 +2 - 4 = 6\)

Step 2: Now, we have \(3 \otimes 6\). Substitute the result from Step 1:

\(3 \otimes 6 = 3 \times 6 + 3 - 6 = 18 + 3 - 6 = 15\)

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