To solve this problem, we multiply and divide the given expression by 2-i:
[tex]\frac{3-4i}{2+i}(\frac{2-i}{2-i}).[/tex]Recall that:
[tex](a+ib)(a-ib)=a^2+b^2.[/tex]Therefore:
[tex]\frac{3-4i}{2+i}(\frac{2-i}{2-i})=\frac{(3-4i)(2-i)}{2^2+1^2}=\frac{(3-4i)(2-i)}{5}.[/tex]Finally, multiplying the factors in the numerator, we get:
[tex]\frac{6-3i-8i-4}{5}.[/tex]Finally, simplifying the above result, we get:
[tex]\frac{2-11i}{5}=\frac{2}{5}-\frac{11}{5}i.[/tex]