(64x-x³)/5x>0 x(64-x²)/5x>0. x≠0 (64-x²)/5>0. 5>0, ⇒64-x²>0 8²-x²>0 (8-x)*(8+x)>0 метод интервалов: 1. (8-х)*(8+х)=0 8-х=0 или 8+х=0 х=8, х=-8 2. - + - ---------------|--------------|------------------->x -8 8 x∈(-8;8)