Intermediate Algebra (12th Edition)

According to page 267, $a^{0}=1$ (where $a$ is a nonzero real number). In other words, we know that any nonzero real number raised to a power of 0 will equal 1. Therefore, $-4^{0}-m^{0}=-(4^{0})-(m^{0})=-(1)-(1)=-1-1=-2$. Recall that the bases of the exponents are 4 and m, respectively, and not -4 and –m.