Rezolva prin metoda reducerii :

f)
-2x+3y=1 | ×3
3x-4y=-1 | ×2
-6x+9y=3
6x-8y=-2
y=1
-2x+3=1
-2x=-2
x=1
g)
x-2y=-5
3x+y=6 | ×2
x-2y=-5
6x+2y=12
7x=7
x=1
1-2y=-5
-2y=-6
y=3
h)
7x-6y=19
x-2y=5 | ×(-3)
7x-6y=19
-3x+6y=-15
4x=4
x=1
1-2y=5
-2y=4
y=-2