2а(а²+b²)-a(a-b)²+a(a+b)²=a(2(a²+b²)-(a-b)²+(a+b)²)=a(2a²+2b²-(a²-2ab+b²)+a²+2ab+b²)=a(2a²+2b²-a²+2ab-b²+a²+2ab+b²)=a(2a²+2b²+4ab)=a·2(a²+b²+2ab)=a·2(a²+2ab+b²)=2a(a+b)²,
если а=-1,5, b=-0,5, то 2·(-1,5)·((-1,5)+(-0,5))²=2·(-1,5)·(-1,5-0,5)²=2·(-1,5)·(-2)²=2·(-1,5)·2²=-1,5·2³=-1,5·8=-12.