Final answer:
The values of x that make the expression (3x)/(x²-4x-12) undefined are x = 6 and x = -2.
Step-by-step explanation:
In order to find the values of x that make the expression (3x)/(x²-4x-12) undefined, we need to identify the values that would make the denominator zero, because dividing by zero is undefined. So we set the denominator equal to zero and solve for x.
x²-4x-12 = 0
We can factor this quadratic equation:
(x-6)(x+2) = 0
Setting each factor equal to zero, we find that x=6 and x=-2.
Therefore, the expression is undefined when x=6 or x=-2.