To add these fractions, we first need to find a common denominator. In this case, the common denominator is 63 (7*9).

So, the expression becomes:

(-3/7)*(4/9) + (-3/7)*(5/9) + (-3/7)*(63/63)

Now, we can multiply the numerators together and the denominators together:

(-3*4)/(7*9) + (-3*5)/(7*9) + (-3*63)/(7*63)

Simplifying each term:

(-12/63) + (-15/63) + (-189/441)

Now, we can add the fractions together:

(-12 - 15 - 189) / 63

= (-216) / 63

= -216/63

= -72/21

= -24/7

Therefore, the final answer is -24/7.