What is the value of a in the proportion? need help!!!

90

Step-by-step explanation:

90-15/90= 5/6

90-15= 75

75/90= 83.3333 or 5/6

if this is really you s much. i only have 3 points left and i have 2 questions to ask

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