# 9th grade math

posted by
**anonymous**
.

Which of the linear systems has exactly one solution

A: -x+y=9

x-y=9

B: -x+y=9

x-y= -9

C: -x+y=9

-x-y=9

D: x-y= -9

-x+y= -9

posted by
**anonymous**
.

Which of the linear systems has exactly one solution

A: -x+y=9

x-y=9

B: -x+y=9

x-y= -9

C: -x+y=9

-x-y=9

D: x-y= -9

-x+y= -9