Can some please help me work out each of these systems?
2. 4x-y=9
Y+2x=12
3. X+3y=13
Y=5-x
4. 3a+b=6
a=10-3b
to do them by elimination, make the following steps:
#2
4x-y = 9
3x+y = 12
add them and eliminate y. Then solve for x.
#3
x+3y = 13
x+y = 5
subtract them and eliminate x, then solve for y
#4
9a+3b = 18
a+3b = 10
subtract and solve for a