y=(2x^2+8x+6)/(x^2+4x+5)求值域

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y=(2x^2+8x+6)/(x^2+4x+5)求值域
y=(2x^2+8x+6)/(x^2+4x+5)求值域

y=(2x^2+8x+6)/(x^2+4x+5)求值域
y=2- 4/(x^2+4x+5);而4/(x^2+4x+5)是大于0而小于等于4
故y=(2x^2+8x+6)/(x^2+4x+5)的值域【-2,2）
不懂再问

(y-2)x²+(4y-8)x+5y-6=0
若y=2，则上式左边=4≠0，所以y≠2
y≠2，将(y-2)t²+(4y-8)t+5y-6=0看成t的二次方程因其在实数范围内有解x
则其判别式Δ=(4y-8)²-4(y-2)(5y-6)≥0
(4y-8)²-4(y-2)(5y-6)=16y²-64y+64-4(5...

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