a^2b^2-ab-20因式分解

分类: 作业答案 • 2022-01-02 16:18:26

问题描述：

a^2b^2-ab-20因式分解

答

a^2b^2-ab-20
=(ab-5)(ab+4)

答

解: 因式分解得
a^2b^2-ab-20
=a^2b^2-2×1/2ab+(1/2)^2-(81/4)
=(ab-1/2)^2-(9/2)^2
=[(ab-1/2)+9/2][(ab-1/2)-9/2]
=(ab+8/2)(ab-10/2)
=(ab+4)(ab-5)

答

a^2b^2-ab-20
=([ab)^2-ab+1/4]-1/4-20
=(ab-1/2)^2-81/4
=(ab-1/2)^2-(9/2)^2
=(ab-1/2-9/2)(ab-1/2+9/2)
=(ab-5)(ab+4)

答

factor(a^2*b^2-a*b-20)

ans =

(a*b+4)*(a*b-5)