若代数式2x的平方-3x+1的值是3,则代数式-4x平方+6x+7的值是?写一下思路。
\u82e5\u4ee3\u6570\u5f0f2X\u7684\u5e73\u65b9+3X+7\u7684\u503c\u4e3a8\uff0c\u5219\u4ee3\u6570\u5f0f4X\u7684\u5e73\u65b9+6X-9\u7684\u503c\u662f\u89e3\uff1a2X²+3X+7=8\uff0c2X²+3X=1\uff0c
4X²+6X=2(2X²+3X)=2
4X²+6X-9=2-9=-7
2x² - 3x + 1 = 3
2x² - 3x = 2
4x² - 6x = 4
4x² - 6x + 7 = 4 + 7 = 11
因为2x^2-3x+1=3，所以2x^2-3x=2
-2(2x^2-3x)=-2×2=-4，即-4x^2+6x=-4
所以-4x^2+6x+7=-4+7=3
2x�0�5 - 3x + 1 = 3
2x�0�5 - 3x = 2
4x�0�5 - 6x = 4
4x�0�5 - 6x + 7 = 4 + 7 = 11
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