Răspuns:
Explicație pas cu pas:
3x+4y= 10l*2
2x-2y= 2 l* -3
-
6x+8y=20
-6x+6y= -6
/ 14y= 14
y= 14/14
y= 1
2x-2*1= 2
2x-2=2
2x=2+2
2x=4
x=4/2
x= 2
S= {2,1}
b)
7x-2y=18 l *9
9x-7y=32 l* -7
63x-18y= 162
-63x+49y=- 224
/ 31y=-62
y= -62/31
y= -2
9x-7*(-2) =32
9x+14=32
9x= 32-14
9x= 18
x= 18/9
S= { 2,-2}
