3(x+5y−4)−4x−11+5a+3b−6c+2a−4b+13c

-x + 15y + 7a - b + 7c - 23

Step-by-step explanation:

3(x+5y-4) - 4x - 11 + 5a + 3b - 6c + 2a - 4b + 13c

= 3x + 15y -12 - 4x - 11 + 5a + 3b - 6c + 2a - 4b + 13c

= (3x-4x) + 15y + (5a+2a) + (3b-4b) - (6c - 13c) - (11+12)

= -x + 15y + 7a - b + 7c - 23

Feel free to mark this as brainliest! :D

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18