已知a+b=3,ab=-2,求a^2+b^2及(a-b)^2的值

2025-01-06 16:24:51
推荐回答(4个)
回答1:

解:a²+b²
=(a+b)²-2ab
=3²-2×(-2)
=9+4
=13
(a-b)²
=(a+b)²-4ab
=3²-4×(-2)
=9+8
=17

回答2:

a²+b²
=(a+b)²-2ab
=3²-2×(-2)
=9+4
=13
(a-b)²
=(a+b)²-4ab
=3²-4×(-2)
=9+8
=17

回答3:

a^2+b^2
=(a+b)^2-2ab
=9-2*(-2)
=13

(a-b)^2
=a^2+b^2-2ab
=13+4
=17

回答4:

a^2+b^2=(a+b)²-2ab=3²+4=13
(a-b)^2=a²+b²-2ab=13+4=17