The complete question is shown in the figure attached with.
The step by step solution to solve the problem is listed below:
[tex]2.5*10^{3}+3.5*10^{2} \\ \\
= 10^{2}(2.5*10+3.5) \\ \\
= 10^{2}(25+3.5) \\ \\
= 10^{2} (28.5) \\ \\
=2.85*10^{3} \\ \\
=2.9*10^{3} [/tex]
