# What is the standard form of a polynomial  (j + 7)(j – 7) ?

Mar 29, 2016

$\left(j + 7\right) \left(j - 7\right) = \left({j}^{2} + {7}^{2}\right) = 49 + {j}^{2}$

If as complex number form then
$\left(j + 7\right) \left(j - 7\right) = 48$

#### Explanation:

Compare to $\left({a}^{2} - {b}^{2}\right) = \left(a - b\right) \left(a + b\right)$

So $\left(j + 7\right) \left(j - 7\right) = \left({j}^{2} + {7}^{2}\right) = 49 + {j}^{2}$

If you are using $j$ as the same as complex number $i$

Then ${j}^{2} = - 1$ giving:

$\left(j + 7\right) \left(j - 7\right) = 48$