Answer:
x=5 y=-6
Step-by-step explanation:
3x+y=9 ------eqn1
y=4-2x -------eqn2
using substitution
put y=4-2x into eqn1
3x+4-2x=9
x=5
put x=5 into eqn2
y=4-2(5)
y=4-10
y=-6
