Simplify b^-21*4^-15

$b^{- 21} \cdot 4^{- 15}$

Rewrite the expression using the negative exponent rule $b^{- n} = \frac{1}{b^{n}}$ .

$\frac{1}{b^{21}} \cdot 4^{- 15}$

Rewrite the expression using the negative exponent rule $b^{- n} = \frac{1}{b^{n}}$ .

$\frac{1}{b^{21}} \cdot \frac{1}{4^{15}}$

Combine.

$\frac{1 \cdot 1}{b^{21} \cdot 4^{15}}$

Simplify the expression.

Multiply $1$ by $1$ .

$\frac{1}{b^{21} \cdot 4^{15}}$

Raise $4$ to the power of $15$ .

$\frac{1}{b^{21} \cdot 1073741824}$

Move $1073741824$ to the left of $b^{21}$ .

$\frac{1}{1073741824 b^{21}}$