# How do you evaluate a^4 – b^2 if a = 3 and b = 9?

Jan 4, 2016

${a}^{4} - {b}^{2} = 0$

#### Explanation:

$G i v e n ,$

$a = 3 , b = 9$

$T h e n , {a}^{4} = 3 \cdot 3 \cdot 3 \cdot 3 = 81$

${b}^{2} = 9 \cdot 9 = 81$

$S o , 81 - 81 = 0$