怎样打印加密的pdf文件:一道初三化简题 过程!!!

来源:百度文库 编辑:中科新闻网 时间:2024/04/28 09:18:10
已知64^2=x^6=8^y,化简:[y(x^2+1/25y)-(x-1/5y)^2-(x+1/5y)^2]÷(-3x)

应该是求解吧,由前式可得x=±4,y=4
因此
x=4时
[y(x^2+1/25y)-(x-1/5y)^2-(x+1/5y)^2]÷(-3x)
=[y(x^2+1/25y)-2*x^2-2/25*y^2]÷(-3x)
=[(y-2)*x^2-1/25*y^2]÷(-3x)
=[(4-2)*4^2-1/25*4^2]÷(-3*4)
=[(4-2)*4-1/25*4]÷(-3)
=196/25÷(-3)
=-196/75
x=-4时,
[y(x^2+1/25y)-(x-1/5y)^2-(x+1/5y)^2]÷(-3x)

=196/75

x=+ -4,y=4
x=4,-6407/2400
x=-4,6407/2400

^ 什么意思?