(4x+y)²+3(4x+y)-4=0,则4x+y值为( ).① (4x+y)²+3(4x+y)-4=0,则4x+y值为( ) 变式1:(a²+b²)²-(a²+b²)-6=0,则a²+b²=() 变式2:(x+y)(2-x-y)+3=0
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![(4x+y)²+3(4x+y)-4=0,则4x+y值为( ).① (4x+y)²+3(4x+y)-4=0,则4x+y值为( ) 变式1:(a²+b²)²-(a²+b²)-6=0,则a²+b²=() 变式2:(x+y)(2-x-y)+3=0](/uploads/image/z/3767824-64-4.jpg?t=%EF%BC%884x%2By%EF%BC%89%26%23178%3B%2B3%EF%BC%884x%2By%EF%BC%89-4%3D0%2C%E5%88%994x%2By%E5%80%BC%E4%B8%BA%EF%BC%88+%EF%BC%89.%E2%91%A0+%EF%BC%884x%2By%EF%BC%89%26%23178%3B%2B3%EF%BC%884x%2By%EF%BC%89-4%3D0%2C%E5%88%994x%2By%E5%80%BC%E4%B8%BA%EF%BC%88+%EF%BC%89+%E5%8F%98%E5%BC%8F1%EF%BC%9A%EF%BC%88a%26%23178%3B%2Bb%26%23178%3B%EF%BC%89%26%23178%3B%EF%BC%8D%EF%BC%88a%26%23178%3B%EF%BC%8Bb%26%23178%3B%EF%BC%89%EF%BC%8D6%3D0%2C%E5%88%99a%26%23178%3B%EF%BC%8Bb%26%23178%3B%EF%BC%9D%EF%BC%88%EF%BC%89+%E5%8F%98%E5%BC%8F2%EF%BC%9A%EF%BC%88x%EF%BC%8By%EF%BC%89%EF%BC%882-x-y%EF%BC%89%EF%BC%8B3%3D0)
(4x+y)²+3(4x+y)-4=0,则4x+y值为( ).① (4x+y)²+3(4x+y)-4=0,则4x+y值为( ) 变式1:(a²+b²)²-(a²+b²)-6=0,则a²+b²=() 变式2:(x+y)(2-x-y)+3=0
(4x+y)²+3(4x+y)-4=0,则4x+y值为( ).
① (4x+y)²+3(4x+y)-4=0,则4x+y值为( )
变式1:(a²+b²)²-(a²+b²)-6=0,则a²+b²=()
变式2:(x+y)(2-x-y)+3=0,则x+y的值为()
变式3:x²+xy+y=14,y²+xy+x=28,则x+y值为()
(4x+y)²+3(4x+y)-4=0,则4x+y值为( ).① (4x+y)²+3(4x+y)-4=0,则4x+y值为( ) 变式1:(a²+b²)²-(a²+b²)-6=0,则a²+b²=() 变式2:(x+y)(2-x-y)+3=0
原题:题目只求x+y,就把(4x+y)当作一个整体,设为t.
t^2+3t-4=0
(t-1)(t+4)=0
解得 t=1 或 t=-4
——-————————变式可先试解,答案如下——————————————
1:设(a^2+b^2)为t
t^2-t-6=0 t=2或t=-3
2:设(x+y)为t
t(2-t)+3=0 t=-1或t=3
3:设(x+y)=t
(x^2+xy+y)+(y^2+xy+x)=14+28=42
(x^2+2xy+y^2)+(x+y)=42
t^2+t=42 t=6
注:“^2"即“平方”
(4x+y)²+3(4x+y)-4=0,则4x+y值为( -4或1 )
设4x+y=a
则:a²+3a-4=0
(a+4)(a-1)=0
∴a=-4或a=1