(x-1)/(x-2)-3x/(x+2)=1/2
x≠2,x≠-2
2(x-1)(x+2)-6x(x-2)=x²-4
2x²+4x-2x-4-6x²+12x-x²+4=0
-5x²+14x=0
-x(5x-14)=0
x=0
x=2,8
7+2x=8-15-5x
2x+5x=8-15-7
7x=-14
x=-14/7
x=-2
3^(5-2x)=9^x
3^(5-2x)=3^2x
5-2x=2x
4x=5
x=5/4=1.25
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x - любое число
13920 100\%
x 13\%
x=(13920·13)/100=1809.6р уб