Вправи: 309

309. Спростіть вираз.

а) a- ba • (aa- b + ab) = a- ba • ab+ a2- abb(a- b) = a- ba • a2(a- b)b = ab;

б) (xy – xx+ y) • x+ yx = x2+ xy- xyy(x+ y) • x+ yx = x2y • 1x = xy;

в) (x+ yx- y + x- yx+ y) : 2x2-y2 = (x+ y)2+ (x- y)2x2- y2 • x2- y22 = x2+2xy+ y2+x2-2xy+y2 1 • 12 = 2x2+ 2y22 = x² + y²;

г) (a- ba+ b – a+ ba- b) : 4a2-b2 = (a- b)2-(a+ b)2 a2- b2 • a2- b24 = a2-2ab+b2-a2-2ab- b2 4 = –ab.