Question

Решите систему. xy=12, 2x+2y-12=2.

Answer 1

2X + 2Y = 14

2( X + Y) = 7*2

X + Y = 7

Y = 7 - X

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XY = 12

X*(7 - X) = 12

7X - X^2 = 12

- X^2 + 7X - 12 = 0

D = 7^2 - 4 * (-1)* (-12) = 49 -4*12 = 49 - 48 = 1

X1 = (-7 + 1) \ - 2 =  - 6 \ - 2 = 3

X2 = (-7 - 1) \ - 2 = - 8 \ - 2 = 4

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Y1 = 7 - 3 = 4

Y2 = 7 - 4 = 3