Question

Rezolvati prin metoda reducerii sistemele : 2x+3y =5 si 5x+2y=-2

Answer 1

2x+3y=5   I*2
5x+2y=-2  I*-3
________________
4x+6y=10
-15x-6=6
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-11x /=16
x=-16/11

2x+3y=5    unde x=16/11
2*(-16/11)+3y=5
-32/11+3y=5
-32+33y=55
33y=55+32
33y=87
y=87/33

y=29/11

Answer 2

2x+3y=5 
5x+2y=-2 

inmultesti prima linie cu -1 si vine 

-2x-3y=-5
5x+2y=-2

le aduni intre ele si o sa vina 
5x-2x+2y-3y=-7=>3x-y=-7=>

=> 3x= -7+y / totul inmultesti cu (-1)
-3x = 7+y 
-x= (7+y)/3