判断函数y=(x-5)(2-x)的单调性?

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判断函数y=(x-5)(2-x)的单调性?判断函数y=(x-5)(2-x)的单调性?判断函数y=(x-5)(2-x)的单调性?y=-x²+7x-10=-(x²-7x+49/4)+4

判断函数y=(x-5)(2-x)的单调性?
判断函数y=(x-5)(2-x)的单调性?

判断函数y=(x-5)(2-x)的单调性?
y=-x²+7x-10
=-(x²-7x+49/4)+49/4-10
=-(x-7/2)²+9/4
开口向下,对称轴x=7/2
所以
x7/2,y是减函数

1、 (a+1)2+2(a+1)(1-a)+3(a-1)2
=a2+2a+1+2-2a2+3a2-6a+3
=2a2-4a+6
2、 5(x-2)2-3(x+1)(x-1)-2(x-1)2
=5(x2-4x+4)-3(x2-1)-2(x2-2x+1)
=5x2-20x+20-3x2+3-2x2+4x-2
=-16x+21