Răspuns:
Explicație pas cu pas:
a)
-2x+9y=7 (4) -8x+36y=28
8x-5y=3 8x-5y=3
...................................
31y=31 y=1
8x-5=3 8x=8 x=1
b)
5x+9y=-6
12x-9y=-45
....................
17x=-51 x=-3
-15+9y=-6 9y=9 y=1
c)
6x-5y=17
-6x+14y=-26
.....................
9y=-9 y=-1
6x+5=17 6x=12 x=2
d)
6x-4y=26
8x+4y=16
.................
14x=42 x=3 9-2y=13 -2y=4 y=-2
