Ma gandesc ca sunt 2 sisteme.
1) x+y+10=15
5x+8y-1=0
inmultesc prima ecuatie cu 5
si voi avea:
5x+8y-1=0
5x+5y+50=75
le scad
0+3y-1-50=0-75
3y-51=-75
3y=-75+51
3y=-24
y = - 24 : 3
y= -8
stiu ca x+y+10=15
x-8+10=15
x+2=15
x=15-2
x=13
2) 2x-3y+4=0
4x-2y+6=0
inmultesc prima ecuatie cu 2
4x-6y+8=0
4x-2y+6=0
le scad
-6y-(-2y)+8-6=0
-6y+2y+2=0
-4y =-2
y = -2 : (-4)
y = 2:4
y = [tex] \frac{1}{2} [/tex]
stiu ca 4x -2y +6=0
[tex]4x-2 * \frac{1}{2} +6=0[/tex]
4x-1+6=0
4x=-6+1
4x = -5
x= [tex] \frac{-5}{4} [/tex]
