<span>7(2y-x)-((5y-3x)-4(x+y))=14у-7х-(5у-3х-4х-4у)=14у-7х-(у-7х)=14у-7х-у+7х=13у.</span>
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
Смотрите решение в прикреплённом файле.
196-a^2=(14-а)^2(((((((((((