因式分解(x2+3x+2)(4x2+8x+3)-90(x2+3x+2)(4x2+8x+3)-90=(x+1)(x+2)(2x+1)(2x+3)-90=(x+1)(2x+3)(x+2)(2x+1)-90=(2x²+5x+3)(2x²+5x+2)-90=(2x²+5x)²+5(2x²+5x)-84=(2x²+5x+12)(2x²+5x-7)=(2x²+5x+12)(2x+7)(x-1)从第四
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/27 10:45:06
![因式分解(x2+3x+2)(4x2+8x+3)-90(x2+3x+2)(4x2+8x+3)-90=(x+1)(x+2)(2x+1)(2x+3)-90=(x+1)(2x+3)(x+2)(2x+1)-90=(2x²+5x+3)(2x²+5x+2)-90=(2x²+5x)²+5(2x²+5x)-84=(2x²+5x+12)(2x²+5x-7)=(2x²+5x+12)(2x+7)(x-1)从第四](/uploads/image/z/1653510-30-0.jpg?t=%E5%9B%A0%E5%BC%8F%E5%88%86%E8%A7%A3%28x2%2B3x%2B2%29%284x2%2B8x%2B3%29-90%28x2%2B3x%2B2%29%284x2%2B8x%2B3%29-90%3D%28x%2B1%29%28x%2B2%29%282x%2B1%29%282x%2B3%29-90%3D%28x%2B1%29%282x%2B3%29%28x%2B2%29%282x%2B1%29-90%3D%282x%26%23178%3B%2B5x%2B3%29%282x%26%23178%3B%2B5x%2B2%29-90%3D%282x%26%23178%3B%2B5x%29%26%23178%3B%2B5%282x%26%23178%3B%2B5x%29-84%3D%282x%26%23178%3B%2B5x%2B12%29%282x%26%23178%3B%2B5x-7%29%3D%282x%26%23178%3B%2B5x%2B12%29%282x%2B7%29%28x-1%29%E4%BB%8E%E7%AC%AC%E5%9B%9B)
因式分解(x2+3x+2)(4x2+8x+3)-90(x2+3x+2)(4x2+8x+3)-90=(x+1)(x+2)(2x+1)(2x+3)-90=(x+1)(2x+3)(x+2)(2x+1)-90=(2x²+5x+3)(2x²+5x+2)-90=(2x²+5x)²+5(2x²+5x)-84=(2x²+5x+12)(2x²+5x-7)=(2x²+5x+12)(2x+7)(x-1)从第四
因式分解(x2+3x+2)(4x2+8x+3)-90
(x2+3x+2)(4x2+8x+3)-90
=(x+1)(x+2)(2x+1)(2x+3)-90
=(x+1)(2x+3)(x+2)(2x+1)-90
=(2x²+5x+3)(2x²+5x+2)-90
=(2x²+5x)²+5(2x²+5x)-84
=(2x²+5x+12)(2x²+5x-7)
=(2x²+5x+12)(2x+7)(x-1)从第四步开始我看不懂了.我个人做法是把2x²+5x+2看做一个整体y,然后用y代入.从第四步开始.
因式分解(x2+3x+2)(4x2+8x+3)-90(x2+3x+2)(4x2+8x+3)-90=(x+1)(x+2)(2x+1)(2x+3)-90=(x+1)(2x+3)(x+2)(2x+1)-90=(2x²+5x+3)(2x²+5x+2)-90=(2x²+5x)²+5(2x²+5x)-84=(2x²+5x+12)(2x²+5x-7)=(2x²+5x+12)(2x+7)(x-1)从第四
=(2x²+5x+3)(2x²+5x+2)-90
=[ (2x²+5x) +3 ] [(2x²+5x) +2 ] -90
=(2x²+5x)²+2(2x²+5x) +3(2x²+5x) +6 -90
=(2x²+5x)²+5(2x²+5x)-84
令y=2x²+5x,
=y²+5y-84=(y+12)(y-7)
原式=(2x²+5x+12)(2x²+5x-7)
又2x²+5x-7=(2x+7)(x-1)
所以原式==(2x²+5x+12)(2x+7)(x-1)
把2x²+5x看做一个整体y
第四步开始使用了十字相乘法,把2x平方 5x看作一个整体,十字相乘法可上百度了解,相信凭楼主的智商不难理解