a^2-b^2=20
利用因式分解得到:
(a-b)(a+b)=20
因为a+b=-5
所以:
(a-b)*(-5)=20
所以a-b=20/(-5)=-4.
如果a二次方-b二次方=20且a+b=-5那么a-b=
如果a二次方-b二次方=20且a+b=-5那么a-b=
数学人气:940 ℃时间:2020-05-14 16:14:02
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