Solve for A (d+m)A=2N

$(d + m) A = 2 N$

Divide each term in $(d + m) A = 2 N$ by $d + m$ .

$\frac{(d + m) A}{d + m} = \frac{2 N}{d + m}$

Simplify the left side.

Cancel the common factor of $d + m$ .

Cancel the common factor.

$\frac{(d + m) A}{d + m} = \frac{2 N}{d + m}$

Divide $A$ by $1$ .

$A = \frac{2 N}{d + m}$