定义丨abcd丨=ad-bc,若丨x+3 x-1 x+1 x-2丨=5x,求x的值
问题描述:
定义丨abcd丨=ad-bc,若丨x+3 x-1 x+1 x-2丨=5x,求x的值
答
丨x+3 x-1 x+1 x-2丨
=(x+3)(x-2)-(x-1)(x+1)
=x^2+x-6-(x^2-1)
=x-5
=5x
4x=-5
x=-5/4