Heyyy can somebody answer this please ?

number 9 is c.

im not really sure what 10 is

9. (3,-4) which is C

10.  (8,-4) which is A

For number 9:

I did elimination by taking one of the "answers" so for (3,-4) x=3 and y= -4

i plugged them in the equation so:

-10(3) -3(-4)= -18 **now we just solve**

-30+12 **its +12 because negative and negative= positive**

-30+12= -18

For number 10:

same steps as before i plugged (8,-4) so:

3(8)- (-4)- 28

24+4= 28

answer: idk

step-by-step explanation:

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