If X \(\ast\) Y = X + Y - XY, find x when (x \(\ast\) 2) + (x \(\ast\) 3) = 68

  • A 24
  • B 22
  • C -12
  • D -21
jamb 1997mathematics

The correct answer is D. -21

x \(\ast\) y = x + y - xy

(x \(\ast\) 2) + (x \(\ast\) 3) = 68

= x + 2 - 2x + x + 3 - 3x

= 86

3x = 63

x = -21

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