Tìm hệ số chứa ${{x}^{9}}$ trong khai triển
${{\left( 1+x \right)}^{9}}+{{\left( 1+x \right)}^{10}}+{{\left( 1+x \right)}^{11}}+{{\left( 1+x \right)}^{12}}+{{\left( 1+x \right)}^{13}}+{{\left( 1+x \right)}^{14}}+{{\left( 1+x \right)}^{15}}$.
A. 3000.
B. 8008.
C. 3003.
D. 8000.
${{\left( 1+x \right)}^{9}}+{{\left( 1+x \right)}^{10}}+{{\left( 1+x \right)}^{11}}+{{\left( 1+x \right)}^{12}}+{{\left( 1+x \right)}^{13}}+{{\left( 1+x \right)}^{14}}+{{\left( 1+x \right)}^{15}}$.
A. 3000.
B. 8008.
C. 3003.
D. 8000.
Loga
Hóa Học lớp 12
