Answer: 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