分解因式:4(3x²-x-1)(x²+2x-3)-(4x²+x-4)²
问题描述：
分解因式:4(3x²-x-1)(x²+2x-3)-(4x²+x-4)²
答
令t=4x²+x-4
原式=4[t-(x²+2x-3)](x²+2x-3)-t²
=-t²+4t(x²+2x-3)-4(x²+2x-3)²
=-[t²-4t(x²+2x-3)+4(x²+2x-3)²]
=-[t-2(x²+2x-3)]²
=-(4x²+x-4-2x²-4x+6)²
=-(2x²-3x+2)²
答
看一看( 3x" - x - 1 ) + ( x" + 2x - 3 ) = 4x" + x - 4发现了什么吗?4( 3x" - x - 1 )( x" + 2x - 3 ) - ( 4x" + x - 4 )"题目想到了怎么办吗?= 4[ ( 4x" + x - 4 ) - ( x" + 2x - 3 ) ]( x" + 2x - 3 ) - ( 4x" +...