先化简.在求值(1)9x+6x²-3(x-2/3x-2²),其中X=-2 (2)1/4(-4x²=2x-8)-(1/2x-1),其中X=1/2(3)(5a²-3b²)+(a²+b²)-(5a²+3b²),其中a=-1,b=1(4)2(a²b+ab²)-2(a²b-1)-2ab²-2,其中a
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![先化简.在求值(1)9x+6x²-3(x-2/3x-2²),其中X=-2 (2)1/4(-4x²=2x-8)-(1/2x-1),其中X=1/2(3)(5a²-3b²)+(a²+b²)-(5a²+3b²),其中a=-1,b=1(4)2(a²b+ab²)-2(a²b-1)-2ab²-2,其中a](/uploads/image/z/5327880-24-0.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80.%E5%9C%A8%E6%B1%82%E5%80%BC%281%299x%2B6x%26%23178%3B-3%28x-2%2F3x-2%26%23178%3B%29%2C%E5%85%B6%E4%B8%ADX%3D-2+%282%291%2F4%28-4x%26%23178%3B%3D2x-8%29-%281%2F2x-1%29%2C%E5%85%B6%E4%B8%ADX%3D1%2F2%283%29%EF%BC%885a%26%23178%3B-3b%26%23178%3B%EF%BC%89%2B%EF%BC%88a%26%23178%3B%2Bb%26%23178%3B%29-%EF%BC%885a%26%23178%3B%2B3b%26%23178%3B%EF%BC%89%2C%E5%85%B6%E4%B8%ADa%3D-1%2Cb%3D1%284%292%28a%26%23178%3Bb%2Bab%26%23178%3B%29-2%EF%BC%88a%26%23178%3Bb-1%29-2ab%26%23178%3B-2%2C%E5%85%B6%E4%B8%ADa)
先化简.在求值(1)9x+6x²-3(x-2/3x-2²),其中X=-2 (2)1/4(-4x²=2x-8)-(1/2x-1),其中X=1/2(3)(5a²-3b²)+(a²+b²)-(5a²+3b²),其中a=-1,b=1(4)2(a²b+ab²)-2(a²b-1)-2ab²-2,其中a
先化简.在求值
(1)9x+6x²-3(x-2/3x-2²),其中X=-2
(2)1/4(-4x²=2x-8)-(1/2x-1),其中X=1/2
(3)(5a²-3b²)+(a²+b²)-(5a²+3b²),其中a=-1,b=1
(4)2(a²b+ab²)-2(a²b-1)-2ab²-2,其中a=-2,b=2
先化简.在求值(1)9x+6x²-3(x-2/3x-2²),其中X=-2 (2)1/4(-4x²=2x-8)-(1/2x-1),其中X=1/2(3)(5a²-3b²)+(a²+b²)-(5a²+3b²),其中a=-1,b=1(4)2(a²b+ab²)-2(a²b-1)-2ab²-2,其中a
(1)9x+6x²-3(x-2/3x-2²),其中X=-2
=9x+6x²-3x+2x+12
=6x²+8x+12 其中X=-2
=6*(-2)²+8*(-2)+12
=24-16+12
=20
(2)1/4(-4x²-2x-8)-(1/2x-1),其中X=1/2
=-x²-1/2x-2-1/2x+1
=-x²-x-1 其中X=1/2
=-(1/2)²-1/2-1
=-1/4-1/2-1
=-7/4
(3)(5a²-3b²)+(a²+b²)-(5a²+3b²),其中a=-1,b=1
=5a²-3b²+a²+b²-5a²-3b²
=a²-5b² 其中a=-1,b=1
=(-1)²-5*1²
=1-5
=-4
(4)2(a²b+ab²)-2(a²b-1)-2ab²-2,其中a=-2,b=2
=2a²b+2ab²-2a²b+2-2ab²-2
=0
(1)9x+6x²-3(x-2/3x-2x²),其中X=-2
=9x+6x²-3x+2x+6x²
=6x²+6x²+9x-3x+2x
=12x²+8x
=12*(-2)²+8*(-2)
=48-16
=32
(2)1/4(-4x²+2x-8)-(1/2...
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(1)9x+6x²-3(x-2/3x-2x²),其中X=-2
=9x+6x²-3x+2x+6x²
=6x²+6x²+9x-3x+2x
=12x²+8x
=12*(-2)²+8*(-2)
=48-16
=32
(2)1/4(-4x²+2x-8)-(1/2x-1),其中X=1/2
=-x²+1/2x-2-1/2x+1
=-x²+1/2x-1/2x+1-2
=-x²-1
=-(1/2)²-1
=-1/4-1
=-5/4
(3)(5a²-3b²)+(a²+b²)-(5a²+3b²),其中a=-1,b=1
=5a²-3b²+a²+b²-5a²-3b²
=5a²-5a²+a²-3b²+b²-3b²
=a²-5b²
=(-1)²-5*1²
=1-5
=-4
(4)2(a²b+ab²)-2(a²b-1)-2ab²-2,其中a=-2,b=2
=2a²b+2ab²-2a²b+2-2ab²-2
=2a²b-2a²b+2ab²-2ab²-2+2
=0
收起
挺好的