To solve the equation, we can start by getting rid of the fractions. We can do this by multiplying both sides of the equation by the least common denominator (LCD) of 12, 15, and 20, which is 60.

So, multiplying both sides of the equation by 60, we get:

60 * (7/12) + 60 * (x/15) = 60 * (1/20)

Simplifying each term, we have:

(60/12) * 7 + (60/15) * x = 60/20

Simplifying further, we get:

5 * 7 + 4 * x = 3

35 + 4x = 3

Next, we can isolate the variable by subtracting 35 from both sides of the equation:

35 + 4x - 35 = 3 - 35

4x = -32

Finally, we can solve for x by dividing both sides of the equation by 4:

4x/4 = -32/4

x = -8

Therefore, the solution to the equation is x = -8.