y= -10x2+2400x-135000,当求x是多少时y最大。麻烦写下接替过程哦,谢谢谢谢了,大神帮忙啊

-10x2是负十*x的平方,谢谢哦~
2024-11-15 09:18:40
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回答(1):

y=-10(x-240x+13500) =-10(x-240x+14400)-9000 =-10(x-120)-9000 ∴当x=120时,y最大,y=-9000