Evaluate the expression (1.3 x 10^{2})(2.5 x 10^{1}).

Evaluate the expression (4.2x10^{3})(1.6x10^{4}).

Evaluate the expression 3(2.5x10^{4}).

Multiply the coefficient 2.5 by 3, and adjust the exponent of 10 if needed. Note that we do not multiply both factors by 3, since no addition or subtraction is involved.