Question

what is twice 2^30? write using exponents. explain your reasoning.

Answer 1

Twice a number is that number multiplied by two. So, we have

$2\cdot 2^{30}$

When you multiply powers of the same base, you sum the exponents:

$a^b \cdot a^c = a^{b\cdot c}$

Which in your case means

$2^1 \cdot 2^{30} = 2^{1+30} = 2^{31}$