(b^12c^3)(b^7c)

To multiply these expressions, we add the exponents of the common base, which in this case is b and c.

For b, we add the exponents 12 and 7:
b^12 * b^7 = b^(12+7) = b^19

For c, we add the exponents 3 and 1:
c^3 * c = c^(3+1) = c^4

So, the simplified expression is b^19 * c^4.