Solve the system of equations using subtraction. 3y = -1/2x + 2 y= -x + 9 a. (10,-1) b. (-1, 8) c. ( 20,-4) d. (3,6)

Mult the first eqn by -2, obtaining -6y = x - 4.

Combine this result with the 2nd equation:

-6y = x - 4
Y= -x + 9

-5y = 5, so y = -1.  Subbing this result for y into the 2nd eqn, we get
-1 = -x + 9, or -x = -10, or x = 10.

the solution is then (10, -1).