1.x(a-b)-y(b-a)+z(a-b)2.已知a+b=1,ab=-1/2,求a(a+b)(a-b)-a(a+b)^2

1.x(a-b)-y(b-a)+z(a-b)2.已知a+b=1,ab=-1/2,求a(a+b)(a-b)-a(a+b)^2
1.x(a-b)-y(b-a)+z(a-b)
2.已知a+b=1,ab=-1/2,求a(a+b)(a-b)-a(a+b)^2

1.x(a-b)-y(b-a)+z(a-b)2.已知a+b=1,ab=-1/2,求a(a+b)(a-b)-a(a+b)^2
1.x(a-b)-y(b-a)+z(a-b)
=x(a-b)+y(a-b)+z(a-b)
=(x+y+z)(a-b)
2.已知a+b=1,ab=-1/2,求a(a+b)(a-b)-a(a+b)^2
a(a+b)(a-b)-a(a+b)^2
=a(a²-b²)-a(a²+2ab+b²)
=a(-b²-2ab-b²)
=a(-2b²-2ab)
=-2ab(a+b)
=-2*(-1/2)*1
=1

1. (x+y+z)(a-b)
2. (a+b)(a^2-ab-a^2-ab)=-2ab(a+b)=1

1=(a-b)(x+y+z)
2=a(a+b)[(a-b)-(a+b)]
=-2ab(a+b)
=1