Question

rozwiaz uklad rownan metodą podstawiania:

x+y/2 -x/3 = 4
{
x-y/2 + y/3 = -3
wynik musi wyjść:

x=-3

y=9

Answer 1

( x + y)/2 - x/3 = 4  / * 6

(x - y)/2 + y/3 = - 3  / * 6

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3x + 3 y - 2 x = 24

3 x - 3 y + 2 y = - 18

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x + 3 y = 24  => x = 24 - 3 y

3 x - y = - 18

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3*( 24 - 3 y) - y = - 18

72 - 9 y - y = - 18

72 - 10 y = - 18

10y = 72 + 18

10 y = 90 / : 10

y = 9

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x = 24 - 3*9 = 24 - 27 = - 3

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Odp. x = - 3, y = 9

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