To decorate a cake, you make a shade of purple icing using 2 drops of red food coloring for every 3 drops of blue.

For 12 drops of red food coloring, how many drops of blue food coloring would you need?

18 drops

Step-by-step explanation:

Make a proportion

We need 2 drops of red for every 3 drops of blue, and 12 drops of red needs x drops of blue

2/3=12/x

Cross multiply

2*x=3*12

2x=36

To solve for x, we need to get x by itself. It is being multiplied by 2. To undo this, divide both sides by 2. This is because the opposite of multiplication is division.

2x/2=36/2

x= 18

For 12 drops of red, 18 drops of blue are needed

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

y∈r, 8> y≥0

hope i !

p.s the first bit only matters if you know what that means.

p.p.s brainliest would really