Răspuns:
a)y=5-4x
2x-15+12x=13 ; 14x=28 =>x=2; y=(-3)
b)3x=5-2y =>x=(5-2y)/3
(25-10y)/3 - 3y = 2
25-10y-9y=6
-19y= -19 =>y=1 ; x=1
c)4x=10-2y sau 2x=5-y =>x=(5-y)/2
5-y+3y=1 =>y=(-2); x=7/2
d)4x=2y-2 sau 2x=y-1 =>x=(y-1)/2
(3y-3)/2 + y = -9
3y-3+2y=-18
5y=-15 =>y=(-3); x=(-2)
e)x=(6+3y)/4
(30+15y)/4 - 7y = 1
30+15y-28y=4
-13y=-26 =>y=2; x=3
f)x=-1-3y
-2-6y-y=5
-7y=7 =>y=(-1); x=2
g)x=-13-5y
-26-10y-3y=13
-13y=39 =>y=(-3); x=2
h)x=10-4y
20-8y-5y=-19
-13y=-39 =>y=3; x=(-2)
