2x的平方-5x-3用十字相乘法因式分解 2x的平方减5x减3进行十字相乘法
\u56e0\u5f0f\u5206\u89e3 2x^4-5x^2+3 \u6211\u77e5\u9053\u8981\u7528\u5341\u5b57\u76f8\u4e58\u6cd5\uff0c\u4f46\u662f\u4ed6\u4eec\u6ca1\u6709\u53ef\u4ee5\u5e73\u65b9\u7684\u89e3\uff1a\u8fd8\u539f\u6cd5\uff1a\u4ee4x^2=t\u3002
x^4=(x^2)^2=t^2
2t^2-5t+3
2 -3
1 -1
-2-3=-5=-5
(2t-3)(t-1)=(2x^2-3)(x^2-1)=2(x^2-3/2)(x+1)(x-1)=2x(x+6^1/2/2)(x-6^1/2/2)(x+1)(x-1)
\u5206\u89e3\u6210\u56db\u4e2a\u56e0\u662f\u7684\u4e58\u673a\u3002
2x\u7684\u5e73\u65b9\u51cf5x\u51cf3
=(2x+1)(x-3)
\u8bf7\u597d\u8bc4
\u5982\u679c\u4f60\u8ba4\u53ef\u6211\u7684\u56de\u7b54\uff0c\u656c\u8bf7\u53ca\u65f6\u91c7\u7eb3\uff0c
~\u5982\u679c\u4f60\u8ba4\u53ef\u6211\u7684\u56de\u7b54\uff0c\u8bf7\u53ca\u65f6\u70b9\u51fb\u3010\u91c7\u7eb3\u4e3a\u6ee1\u610f\u56de\u7b54\u3011\u6309\u94ae~
~\u624b\u673a\u63d0\u95ee\u7684\u670b\u53cb\u5728\u5ba2\u6237\u7aef\u53f3\u4e0a\u89d2\u8bc4\u4ef7\u70b9\u3010\u6ee1\u610f\u3011\u5373\u53ef\u3002
~\u4f60\u7684\u91c7\u7eb3\u662f\u6211\u524d\u8fdb\u7684\u52a8\u529b~~
O(\u2229_\u2229)O\uff0c\u8bb0\u5f97\u597d\u8bc4\u548c\u91c7\u7eb3\uff0c\u4e92\u76f8\u5e2e\u52a9
解：
2 1
×
1 -3
所以
原式=(2x+1)(x-3)
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