# How do you solve \frac { w } { 3} + \frac { 2} { 5} = \frac { 1} { 15}?

Nov 19, 2016

$w = - 1$

#### Explanation:

You need to find the (lowest) common denominator and since $3$ and $5$ are primes and $15 = 3 \cdot 5$ we have $\text{LCD} \left(3 , 5 , 15\right) = 15$. We multiply both sides of the equation by $15$:
$$15\cdot \frac { w } { 3} +15\cdot \frac { 2} { 5} =15\cdot \frac { 1} { 15}$$
$$5w+3 \cdot 2=1$$
$$5w+6=1$$
$$5w=1-6$$
$$5w=-5$$
$$w=-1$$