Question

toate patru...........​

Answer 1

a) {x(x-4)+4+(y-x+1)(x+y)=y(y-6)+10

{(x+y+3)(x-y-2)=(x+y)(x-y)

{x²-4x+4+xy-x²+x+y²-xy+y=y²-6y+10

{x²+xy+3x-xy-y²-3y-2x-2y-6=x²-y²

sus se reduce x² cu -x², y² cu y² de dupa egal, xy cu -xy

jos se reduce x² cu x² dupa egal si -y² cu -y² dupa egal, xy cu -xy

{-4x+4+x+y=-6y+10

{3x-3y-2x-2y-6=0

{-3x+7y=6

{x-5y=6 /×3

{-3x+7y=6

{3x-15y=18

________

-8y=24

y=-3

-3x-21=18

-3x=39

x=-13

b) {x(x+2)+1+y(2-y)=(x+y+1)(x-y+2)+1

{9+(x+y-3)(x-y+5)=(x-y)(x+y)

{x²+2x+1+2y-y²=x²+xy+x-xy-y²-y+2x+2y+2+1

{9+x²+xy-3x-xy-y²+3y+5x+5y-15=x²-y²

Sus reduci x² cu x² dupa egal, -y² cu -y² dupa egal si xy cu -xy

Jos reduci aceleași lucruri

{2x+1+2y=x-y+2x+2y+2+1

{9-3x+3y+5x+5y-15=0

acum sus reduci 2x cu cel de dupa egal si 2y la fel

{x-y=-2

{2x+8y=6 :2

{x-y=-2 /(-1)

{x+4y=3

{-x+y=2

{x+4y=3

______

5y=5

y=1

x+4=3

x=-1