Chapter R - Elementary Algebra Review - R.4 Polynomials - R.4 Exercise Set - Page 961: 41

$-14$

Substituting $a$ with $2$ and $b$ with $-1$, the given expression, $ a^2b^3+2b^2-6a ,$ evaluates to \begin{array}{l}\require{cancel} (2)^2(-1)^3+(2)(-1)^2-6(2) \\\\= (4)(-1)+(2)(1)-6(2) \\\\= -4+2-12 \\\\= -14 .\end{array}