12(!). Find the numerical value of the monomial \(0.007 a^{7} b^{9}\), if \(a=-5, b=2\).
12. Solution. Since the second factor is negative and the third is positive, the numerical value of the monomial is negative. We have:

\(-0,007 \cdot 5^{7} \cdot 2^{9}=-0,007 \cdot 4 \cdot(2 \cdot 5)^{7}=-280000\).