Solve for a na=f^2-Da

$n a = f^{2} - D a$

Step 1

Add $D a$ to both sides of the equation.

$n a + D a = f^{2}$

Step 2

Factor $a$ out of $n a + D a$ .

Factor $a$ out of $n a$ .

$a n + D a = f^{2}$

Factor $a$ out of $D a$ .

$a n + a D = f^{2}$

Factor $a$ out of $a n + a D$ .

$a (n + D) = f^{2}$

Step 3

Divide each term in $a (n + D) = f^{2}$ by $n + D$ and simplify.

Divide each term in $a (n + D) = f^{2}$ by $n + D$ .

$\frac{a (n + D)}{n + D} = \frac{f^{2}}{n + D}$

Simplify the left side.

Cancel the common factor of $n + D$ .

Cancel the common factor.

$\frac{a (n + D)}{n + D} = \frac{f^{2}}{n + D}$

Divide $a$ by $1$ .

$a = \frac{f^{2}}{n + D}$