(I WILL GIVE BRAINLIEST)Solve the system of equations by the addition method.

Answer:
x = -27/2 , y = 9/2
Step-by-step explanation:
x/5 - y/15 = -3 ....... equation (1)
x/3 + y/9 = -4 ...... equation (2)
Substitute x = -15 + y/3
(-15+y/3)/3 + y/9 = -4
Simplify,
(-45+2y)/9 = -4
Isolate y for (-45+2y)/9 = -4
y = 9/2
Substitute y = 9/2
x = -15 + (9/2)/3
x = -27/2
x = -27/2 , y = 9/2