将4个数abcd排成2行2列,两边各加一条竖直线记成将4个数a,b,c,d排成2行、2列,两边各加一条竖直线记成|a b定义|a b|=ad-bc, |c
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![将4个数abcd排成2行2列,两边各加一条竖直线记成将4个数a,b,c,d排成2行、2列,两边各加一条竖直线记成|a b定义|a b|=ad-bc, |c](/uploads/image/z/2713518-54-8.jpg?t=%E5%B0%864%E4%B8%AA%E6%95%B0abcd%E6%8E%92%E6%88%902%E8%A1%8C2%E5%88%97%2C%E4%B8%A4%E8%BE%B9%E5%90%84%E5%8A%A0%E4%B8%80%E6%9D%A1%E7%AB%96%E7%9B%B4%E7%BA%BF%E8%AE%B0%E6%88%90%E5%B0%864%E4%B8%AA%E6%95%B0a%2Cb%2Cc%2Cd%E6%8E%92%E6%88%902%E8%A1%8C%E3%80%812%E5%88%97%2C%E4%B8%A4%E8%BE%B9%E5%90%84%E5%8A%A0%E4%B8%80%E6%9D%A1%E7%AB%96%E7%9B%B4%E7%BA%BF%E8%AE%B0%E6%88%90%7Ca+b%E5%AE%9A%E4%B9%89%7Ca+b%7C%3Dad-bc%2C++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++%7Cc)
将4个数abcd排成2行2列,两边各加一条竖直线记成将4个数a,b,c,d排成2行、2列,两边各加一条竖直线记成|a b定义|a b|=ad-bc, |c
将4个数abcd排成2行2列,两边各加一条竖直线记成
将4个数a,b,c,d排成2行、2列,两边各加一条竖直线记成|a b定义|a b|=ad-bc,
|c d| |c d|
上述记号就叫做2阶行列式.若
|6x+5 6x-1|
|6x-1 6x-5| =-20,则x=多少?
求答案!【和过程……如若正确……追加财富值15……
将4个数abcd排成2行2列,两边各加一条竖直线记成将4个数a,b,c,d排成2行、2列,两边各加一条竖直线记成|a b定义|a b|=ad-bc, |c
由题意可得出:(6x+5)(6x-5)-(6x-1)^2=-20
(36x^2-25)-(36x^2-12x+1)+20=0,-25+12x-1+20=0,即12x+20=26
所以x=1/2