a=3+2倍根号2,b=3-2倍根号2,
ab=(3+2倍根号2)(3-2倍根号2)=9-8=1
a-b=3+2倍根号2-(3-2倍根号2)=4√2
a²b-ab²
=ab(a-b)
=1*4√2
=4√2
a=3+2√2
b=3-2√2
则
ab=(3+2√2)(3-2√2)
=3²-(2√2)²
=9-8
=1
a-b=3+2√2-(3-2√2)
=4√2
所以
a²b-ab²
=ab(a-b)
=1 * 4√2
=4√2
a²b-ab²
=ab(a-b)
= (3+2√2)(3-2√2)(3+2√2-3+2√2)
=(3^2- (2√2)^2)x 4√2
=4√2
=ab*(a-b)=(3^2-(2√2)^2)*(-4√2)=-4√2