先化简再求值[(3a-7)^2-(a+5)^2]\(4a-24)其中a=0.02_数学解答

先化简再求值[(3a-7)^2-(a+5)^2]\(4a-24)其中a=0.02

人气：490 ℃　时间：2020-02-02 20:44:56

解答

[(3a-7)^2-(a+5)^2]\(4a-24)
=[(3a-7+a+5)*(3a-7-a-5)]/(4a-24)
=(4a-2)*(2a-12)/(4a-24)
=(2a-1)(a-6)/(a-6)
=2a-1
=2×0.02-1
=0.04-1
=-0.96