Bài giải:

Ta có: h(x) = f(x) - g(x) = ($5{{x}^{5}}+2{{x}^{4}}+3{{x}^{3}}+2{{x}^{2}}+x+5$) – (${{x}^{3}}+2{{x}^{2}}+x+2$)

= $5{{x}^{5}}+2{{x}^{4}}+3{{x}^{3}}+2{{x}^{2}}+x+5-{{x}^{3}}-2{{x}^{2}}-x-2$

= $5{{x}^{5}}+2{{x}^{4}}+(3{{x}^{3}}-{{x}^{3}})+(2{{x}^{2}}-2{{x}^{2}})+(x-x)+(5-2)$

= $5{{x}^{5}}+2{{x}^{4}}+2{{x}^{3}}+3$

Do đó: h(1) = ${{5.1}^{5}}+{{2.1}^{4}}+{{2.1}^{3}}+3=12$

Vậy đáp án đúng là: C