A) ㏒₃(x²-1)=㏒₃(5x-7);
x²-1=5x-7;
x²-5x+6=0;
x1=3; x2=2;
6m-12-2n+mn=(6m+mn)-(12+2n)=m(6+n)-2(n+6)=(n+6)(m-2)
x² = 30 - x
x² + x - 30 = 0
a = 1; b = 1; c = - 30
D = b² - 4ac = 1² - 4 * 1 * (-30) = 1 + 120 = 121
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x1 = (-1+11)/2
x1 = 10/2
x1 = 5
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x2 = (-1-11)/2
x2 = -12/2
x2 = -6
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Ответ: x1 = 5, x2 = -6.
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