To solve the equation 3/4 * x + 3/5 = 0, we need to isolate the variable x.

First, let's get rid of the fractions by multiplying every term by the least common denominator (LCD) of 4 and 5, which is 20.

20 * (3/4 * x) + 20 * (3/5) = 20 * 0

15x + 12 = 0

Next, let's isolate the variable x by subtracting 12 from both sides of the equation.

15x + 12 - 12 = 0 - 12

15x = -12

Finally, divide both sides of the equation by 15 to solve for x.

(15x)/15 = -12/15

x = -12/15

Simplifying the fraction -12/15, we get:

x = -4/5

Therefore, the solution to the equation 3/4 * x + 3/5 = 0 is x = -4/5.