Help I really don't know how to do this I need help

It would be C for it is the lowest.

Step-by-step explanation:

Since all of these numbers are fractions we can divide them by the denominator and see which one would be the lowest.  If we do that we will end up getting C.

A - 0.5

B - 0.5

C - 0.4

D - 0.45

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