先化简,再求徝:(5y+1)(5y-1)-(5y+25y²),其中y=2/5

问题描述:

先化简,再求徝:(5y+1)(5y-1)-(5y+25y²),其中y=2/5

:(5y+1)(5y-1)-(5y+25y²)
=25y²-1-5y-25y²
=-1-5y
=-1-5x2/5
=-3对的吗?老班要通缉的对的哦,三克油啦☆☆