Question

1)Rezlva sistemele?
x+y=12
x-y=4 prin ambele metode
2)5x+3=y-5
7x-3y=7

Answer 1

[tex]x+y=12 x-y=4 3x/=8 x=8/3 [/tex]

[tex] \frac{8}{3}+y=12 8+3y=36 3y=36-8 3y= 28 y=28/3[/tex]


Al doilea sistem

[tex]5x+3=y-5 7x-3y=7

\left \{ {{ 5x-y=-5-3}\atop{7x-3y=7}} \right.

5x-y=-8 /(-3)

7x-3y=7

-15x+3y=24
7x-3y=7

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-8x/=31


-8x=31 /(-1)

 8x=-31

x= -31/8 [/tex]

[tex]7*( \frac{-31}{8})-3y=7 [/tex]


[tex] \frac{-217}{8}-3y=7 -217-24y=56 -217-24y-56=0 -24y-273=0 -24y=273 /(-1) 24y=-273 y=-273/24[/tex]