Question

初二数学两道题求解一定给好评

Answer 1

9.由已知推得（x+4)²+(y+3)²=0 x=-4 y=-3
∴(x²-4y²)/(x²+4xy+4y²)-x/(x+2y)
=(x+2y)(x-2y)/(x+2y)²-x/(x+2y)
=(x-2y)/(x+2y)-x/(x+2y)
=-2y/(x+2y)
=(-3/5)
10.由已知推得a²+1=3a
所以2a³-5a²-3+3/(a²+1)
=2a³-5(a²+1)+2+3/3a
=2a³-15a+2+1/a
=2(a³+1)-15a+1/a
=2(a+1)(a²-a+1)-15a+1/a
=2(a+1)(2a)-15a+1/a
=4a²+4a-15a+1/a
=4a²+4-11a+1/a-4
=12a-11a+1/a-4
=a+1/a-4=(a²+1)/a-4
=3a/a-4=(-1)

追问

这个全部都是一些不认识的符号肯定是那个电脑传输过来就这个样子了，你可不可以把它们写下来。

追答

9.由已知推得（x+4)²+(y+3)²=0 x=-4 y=-3
∴(x²-4y²)/(x²+4xy+4y²)-x/(x+2y)
=(x+2y)(x-2y)/(x+2y)²-x/(x+2y)
=(x-2y)/(x+2y)-x/(x+2y)
=-2y/(x+2y)
=(-3/5)
10.由已知推得a²+1=3a
所以2a³-5a²-3+3/(a²+1)
=2a³-5(a²+1)+2+3/3a
=2a³-15a+2+1/a
=2(a³+1)-15a+1/a
=2(a+1)(a²-a+1)-15a+1/a
=2(a+1)(2a)-15a+1/a
=4a²+4a-15a+1/a
=4a²+4-11a+1/a-4
=12a-11a+1/a-4
=a+1/a-4=(a²+1)/a-4
=3a/a-4=(-1)
你好我现在不能传拍照版 我又传了一遍 若还是错码 我今天抽空写下来

追问

还是的

追答

追问

恩呢，谢谢