y=2x^2-2x+1 y=-2x^2+2x+1 y=x^2-5x+1/4 y=-x^2-4x=2 y=5x^2-2x+

来源：学生作业帮编辑：作业帮分类：数学作业时间：2024/07/14 15:53:13

y=2x^2-2x+1 y=-2x^2+2x+1 y=x^2-5x+1/4 y=-x^2-4x=2 y=5x^2-2x+1
求二次函数的最值,并指出是最大值还是最小值,我都忘了怎么做、这些都做不来了、帮帮忙、谢谢、、

y=2x^2-2x+1 =2(x-1/2)^2+1/2,最小值y=1/2
y=-2x^2+2x+1=-2(x-1/2)^2+3/2,最大值y=3/2
y=x^2-5x+1/4=(x-5/2)^2-6,最小值y=-6
y=-x^2-4x-2=-(x+2)^2+2,最大值y=2
y=5x^2-2x+1=5(x-1/5)^2+4/5,最小值y=4/5

先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y y=(x^2+x)/(x+1) 已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-( 已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 已知4x=9y求(1)x+y/y (2)y-x/2x {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 1、x(x-y)(x+y)-x(x+y)^2 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知x²+y²+5=2x+4y,求代数式（2x²-（x+y)(x-y))x((x+y-1) 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27