1) (х+2)(х-7)>0
x=-2 x=7
x∈(-∞;-2) U (7;∞)
2) (х+5)(х-8)<0
x=-5 x=8
x∈(-5;8)
1) (a^2-b^2)(a^2+b^2)
2) a(b^2-a^2)=a(b-a)(b+a)
2) x^3 ( y^3 - 2 ) + 5 ( y^3 - 2 ) = (y^3 - 2) (x^3 + 5)
4) 9 ( 3 - x^2 ) + y^6 ( 3 - x^2 ) = (3 - x^2 ) ( 9 +y^6)
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