已知a+b=3,ab=2,则a²b+ab²= ,a的4次方+b的4次方= ,a-b=
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已知a+b=3,ab=2,则a²b+ab²= ,a的4次方+b的4次方= ,a-b=
已知a+b=3,ab=2,则a²b+ab²= ,a的4次方+b的4次方= ,a-b=
已知a+b=3,ab=2,则a²b+ab²= ,a的4次方+b的4次方= ,a-b=
由a+b=3,ab=2;
解得:a、b=1、2;
∴①a²b+ab²=ab﹙a+b﹚=2×3=6
②a^4+b^4=1^4+2^4=17
③a-b=±1
a²b+ab²
=ab(a+b)
=2*3
=6
a^4+b^4
=(a^2+b^2)^2-2a^2b^2
=[(a+b)^2-2ab]^2-2(ab)^2
=(3^2-4)^2-2*2^2
=25-8
=16
a-b
=±√[(a+b)^2-4ab]
=±√(3^2-8)
=±1