Question

need help with this equation please

Answer 1

Step-by-step explanation:

${a}^{16 } \div {a}^{21}$

${a}^{16} \times {a}^{ - 21}$

=

${a}^{ - 21 + 16}$

${a}^{ - 15}$

hope it's helpful to you

have a great day

Answer 2

a^16-21

=a^-4.

=1/a^4.

hope it helps.