Question

de reolvat in rxr sistemul de ecuatii {2*(x-y)=3-x+2y si {x+2y=-7

Answer 1

2*(x-y)=3-x+2*y <=> 2*x-2*y=3-x+2*y <=>3*x-4*y=3
x+2*y=-7 =>x=-7-2*y
Inlocuim pe x in prima ecuatie si avem:
3*(-7-2*y)-4*y=3 <=>-21+6*y-4*y=3 <=> -21+2*y=3 =>2*y=24 =>y=12
x=-7-24= -31
x= -31; y=12
*=inmultire
<=> echivalent cu
=> rezulta
sper ca acum se intelege