If demand function for good X is given by X^D = 1500-1.3P,-1.8P + 2M then we know that?

If demand function for good X is given by X^D = 1500-1.3P,-1.8P + 2M then we know that?

Explanation

If demand function for good X is given by X^D = 1500-1.3P,-1.8P + 2M then we know that goods X and Y are complements to each other.