y=2x³-3x²-12x 14求极值点和极值
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解析:令x+y=m,x-y=n,那么原方程组可化为:{2分之m+3分之n=6(1){2m+n=12(2)(1)×6可得:3m+2n=36(3)(2)×2可得:4m+2n=24(4)(4)-(3)可得:
2x-y/x+3y=2得x+3y/2x-y=1/24x-2y/x+3y减4x+12y除以2x-y=2(2x-y)/x+3y-4(x+3y)/2x-y=2乘以2-4乖以1/2=4-2=2
∵x16-1=(x8)2-1=(x8+1)(x8-1)=(x8+1)[(x4)2-1]=(x8+1)(x4+1)(x4-1)=(x8+1)(x4+1)(x2+1)(x2-1)=(x8+1)(x4+1)
答案是2.4x-2y/x+3y=(2x-y/x+3y)乘以2=4,4x+12y/2x-y=(x+3y/2x-y)乘以4=1/2x4=2,所以代数式等于4-2=2.
3.2X=44.8x=44.8÷3.2x=14x÷304=0.34x=0.34×304x=103.3612×2+6x=36.3624+6x=36.366x=36.36-246x=1236x=12.36
X+Y分之X-Y等于3x=-2yX+Y分之2(x-y)减X+Y分之3X+Y=(-x-3y)/(x+y)=1
.死算呗xy-2x+3y-6=xy+10x-3y-30,2x-y=4xy+3x+y+3=xy+12x-2y-24,3x-y=92式减1式,x=5,y=6
因为(x-y)/(x+y)=3,则(x+y)/(x-y)=1/3则5(x-y)(x+y)-(x+y)/2(x-y)=5*3-1/(3*2)=15-1/6=89/6
设a=x+y,b=x-y原方程组为:a/2+b/3=6,即3a+2b=36,即:12a+8b=1444a-5b=12,即:12a-15b=36相减得:23b=108,得:b=108/23,再得:a=1
x=80/5=166.3/7=x=0.96x=9-3=6x=14x=10-2=8x=25x=39+56=95x=195x=21-18=3x=5/3这一题你换了行我没看懂.7x=3*8.19=24.57
(x÷2+2.8)*14=(x÷2-2.8)*16x÷2*14+39.2=x÷2*16-44.87x+39.2=8x-44.88x-7x=44.8+39.2x=84
解(x-y)(x+y)-(x-2y)²+x(3x-5y)-(x-y)(x-2y)=(x²-y²)-(x²-4xy+4y²)+(3x²-5xy
x^2=12x=±2√3y^2=3y=±√3|x-y|=y-x说明y-x≥0即y≥x所以x不可能等于2√3,即x=-2√3若y=-√3,x+y=-3√3若y=√3,x+y=-√3
xx14分之5=1得5x=14yx15分之14=1得2y=15/75x-2y=14-15/7=(98-15)/7=83/7
6X=3X15X=45/6X=7.575X减3X=1572X=15X=15÷72X=5/247X=25X35X=25X35÷7X=12554X=34X2X=68/54X=34/2712X=23X14X
23x-5X14=1423x-70=1423x=14+7023x=84x=84/23
3y=2x,两边同时乘以1/3x可得y/x=2/3;y/3=x/2,两边同时乘以3/x可得y/x=3/2;12/x=9y,两边都乘以x/9可得x/y=4/3.