对二次三项式4x2-6xy-3y2分解因式正确的是()A.4(x+3+214y)(x+3-214y)B.4(x-21+34y)(x-21-34y)C.(x-3y-21y)(x-3y+21y)D.(2x

题目简介

对二次三项式4x2-6xy-3y2分解因式正确的是()A.4(x+3+214y)(x+3-214y)B.4(x-21+34y)(x-21-34y)C.(x-3y-21y)(x-3y+21y)D.(2x

题目详情

对二次三项式4x2-6xy-3y2分解因式正确的是(  )
A.4(x+
3+
21
4
y)(x+
3-
21
4
y)
B.4(x-
21
+3
4
y)(x-
21
-3
4
y)
C.(x-3y-
21
y)(x-3y+
21
y)
D.(2x-
3-
21
2
y)(2x-
21
+3
2
y)
题型:单选题难度:中档来源:上海模拟

答案

4x2-6xy-3y2
=4[x2-class="stub"3
2
xy+(class="stub"3
4
y)2]-3y2-class="stub"9
4
y2
=4(x-class="stub"3
4
y)2-class="stub"21
4
y2
=(2x-class="stub"3
2
y-
21
2
y)(2x-class="stub"3
2
y+
21
2
y)
=(2x-
3+
21
2
y)(2x-
3-
21
2

故选D.

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