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Ответ:

Объяснение:

1.

((3-x)/x³)*(xy-x)/(3-x)+(3-y)/(3x²)=((3-x)/x³)*(x*(y-1)/(3-x)+(3-y)/(3x²)=

=((3-x)*x*(y-1)/(x³(3-x))+(3-y)/(3x²)=((y-1)/x²)+(3-y)/(3x²)=

(3*(y-1)+3-y)/(3x²)=(3y-3+3-y)/(3x²)=2y/3x².

2.

25x²+13x=13x²+4

12x²+13x-4=0    D=361    √D=19

x₁=0,25    x₂=-4/3.

3.

a) 2*√128-√72=2*√(64*2)-√(36*2)=2*8*√2-6*√2=16√2-6√2=10√2.

б) (6-√3)²=36-2*6*√3+3=39-12√3.