初一的题《多项式乘以多项式》1.先化简,再求值:(2x-1)(4x²+2x+1)其中x=-22.先化简,再求值:(x-y)(x-2y)-2(2x-3y)(x-2y),其中x=-2,y=-3.3.先化简,再求值:(a+b)(a-b)+b(b-2),其中a=-1,b=1.4.先化简,再求值:(x+2
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![初一的题《多项式乘以多项式》1.先化简,再求值:(2x-1)(4x²+2x+1)其中x=-22.先化简,再求值:(x-y)(x-2y)-2(2x-3y)(x-2y),其中x=-2,y=-3.3.先化简,再求值:(a+b)(a-b)+b(b-2),其中a=-1,b=1.4.先化简,再求值:(x+2](/uploads/image/z/3767697-9-7.jpg?t=%E5%88%9D%E4%B8%80%E7%9A%84%E9%A2%98%E3%80%8A%E5%A4%9A%E9%A1%B9%E5%BC%8F%E4%B9%98%E4%BB%A5%E5%A4%9A%E9%A1%B9%E5%BC%8F%E3%80%8B1.%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%86%8D%E6%B1%82%E5%80%BC%3A%282x-1%29%284x%26%23178%3B%2B2x%2B1%29%E5%85%B6%E4%B8%ADx%3D-22.%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%86%8D%E6%B1%82%E5%80%BC%3A%28x-y%29%28x-2y%29-2%282x-3y%29%28x-2y%29%2C%E5%85%B6%E4%B8%ADx%3D-2%2Cy%3D-3.3.%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%86%8D%E6%B1%82%E5%80%BC%3A%EF%BC%88a%2Bb%EF%BC%89%EF%BC%88a-b%29%2Bb%28b-2%29%2C%E5%85%B6%E4%B8%ADa%3D-1%2Cb%3D1.4.%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%86%8D%E6%B1%82%E5%80%BC%3A%EF%BC%88x%2B2)
初一的题《多项式乘以多项式》1.先化简,再求值:(2x-1)(4x²+2x+1)其中x=-22.先化简,再求值:(x-y)(x-2y)-2(2x-3y)(x-2y),其中x=-2,y=-3.3.先化简,再求值:(a+b)(a-b)+b(b-2),其中a=-1,b=1.4.先化简,再求值:(x+2
初一的题《多项式乘以多项式》
1.先化简,再求值:(2x-1)(4x²+2x+1)其中x=-2
2.先化简,再求值:(x-y)(x-2y)-2(2x-3y)(x-2y),其中x=-2,y=-3.
3.先化简,再求值:(a+b)(a-b)+b(b-2),其中a=-1,b=1.
4.先化简,再求值:(x+2)(x-2)-x(x-1),其中x=-1.
初一的题《多项式乘以多项式》1.先化简,再求值:(2x-1)(4x²+2x+1)其中x=-22.先化简,再求值:(x-y)(x-2y)-2(2x-3y)(x-2y),其中x=-2,y=-3.3.先化简,再求值:(a+b)(a-b)+b(b-2),其中a=-1,b=1.4.先化简,再求值:(x+2
1.先化简,再求值:(2x-1)(4x²+2x+1)其中x=-2
(2x-1)(4x²+2x+1)
=8x³-1
=-64-1
=-65
2.先化简,再求值:(x-y)(x-2y)-2(2x-3y)(x-2y),其中x=-2,y=-3.
(x-y)(x-2y)-2(2x-3y)(x-2y)
=(x²-3xy+2y²)-(4x²-14xy+12y²)
=-3x²+11xy-10y²
=-12+66-90
=-36
3.先化简,再求值:(a+b)(a-b)+b(b-2),其中a=-1,b=1.
(a+b)(a-b)+b(b-2)
=a²-b²+b²-2b
=a²-2b
=1-2
=-1
4.先化简,再求值:(x+2)(x-2)-x(x-1),其中x=-1.
(x+2)(x-2)-x(x-1)
=x²-4-x²+x
=x-4
=-5
2x*4x²+2X*2x+2X-4x²-2x-1=-64+16-4-16+4-1=-65
下面的依次类推
1.(2x-1)(4x²+2x+1)其中x=-2
=(2x)^3-1^3
=8x^3-1
=8*(-2)^3-1
=-65
2.:(x-y)(x-2y)-2(2x-3y)(x-2y),其中x=-2,y=-3
=(x-2y)[(x-y)-2(2x-3y)]
=(x-2y)(x-y-4x+6y)
=(x-2y)(5y-3x)
全部展开
1.(2x-1)(4x²+2x+1)其中x=-2
=(2x)^3-1^3
=8x^3-1
=8*(-2)^3-1
=-65
2.:(x-y)(x-2y)-2(2x-3y)(x-2y),其中x=-2,y=-3
=(x-2y)[(x-y)-2(2x-3y)]
=(x-2y)(x-y-4x+6y)
=(x-2y)(5y-3x)
=(-2-(-3)*2)(5*(-3)-3*(-2))
=-36
3.(a+b)(a-b)+b(b-2),其中a=-1,b=1。
=a^2-b^2+b^2-2b
=a^2-2b
=(-1)^2-2*1
=-1
4.(x+2)(x-2)-x(x-1),其中x=-1。
=x^2-4-x^2+x
=x-4
=-1-4
=-5
收起