Resposta:
[tex]\textsf{Leia abaixo}[/tex]
Explicação passo a passo:
[tex]\mathsf{a = -\dfrac{2^{12}.3^{10}.7^{11}}{42^{10}}}[/tex]
[tex]\mathsf{a = -\dfrac{2^{12}.3^{10}.7^{11}}{(2.3.7)^{10}}}[/tex]
[tex]\mathsf{a = -\dfrac{2^{12}.3^{10}.7^{11}}{2^{10}.3^{10}.7^{10}}}[/tex]
[tex]\mathsf{a = -2^{(12 - 10)}.3^{(10 - 10)}.7^{(11 - 10)}}[/tex]
[tex]\mathsf{a = -2^{2}.3^{0}.7^{1}}[/tex]
[tex]\mathsf{a = -4.1.7}[/tex]
[tex]\boxed{\boxed{\mathsf{a = -28}}}\leftarrow\textsf{letra C}[/tex]
