What value would cause the rational expression 8x^2+1/x to be undefined?

x=__

The rational expression 8x^2+1/x would be undefined if the denominator, x, equals 0.

Therefore, x = 0.

The rational expression 8x^2 + 1/x would be undefined when the denominator, which is x, equals zero because division by zero is undefined in mathematics.

Therefore, x = 0 would cause the rational expression to be undefined.