1.
Which of the following systems is (2, -3) a solution? (Choose all that apply)
a. x+y = -1
b. 2x-y=7
c. 10x + 2y = 28
3x + y = 3
5x + y = 14
6x - 3y = 21
d. 9x - 5y = 33
7x + 2y = 8