作业帮1x2 2x3 3x4 ... 18x19 19x20
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/15 19:22:19
1,（1）将（x+3/x-1）设为a（2）得a²-5a+6=0（3）因式分解（a-2）（a-3）=0（4）a1=2a2=32,化简得x³-4x²+18=0
(1)0.25x=-5x=-20(2)3x-4x=1-5x=4(3)3x-4x=18-5x=-13(4)1+7=x+7xx=1(5)9x-7x-3x=-8x=8(6)-x+3x=3-2x=1/2(7)
原式:X^2-5X+6+18=X^2+10X+9-5X+24=10X+915X=15X=1
x²-3x-18≤0(x-6)(x+3)≤0-3≤x≤6-x²+x≥3x+1x²+2x+1≤0(x+1)²≤0x=-1再问：还有（2x+1）分之（2x²
依次为：(x-3)(x+1)；(x+9)(x-2)；(x-4)(x+1)；(x+6)(x-1)；(x-4)(x-9)；(2x+1)(x+1)
如图,两个实数解,x=-2.21946和0.0326566这是个20次的方程,基本没法用手算的.
(X-X*20%-18)-（X-X*20%-18）*10%=X*1/2-3则（X*80%-18）*90%=X*1/2-372%*X-16.2=X*1/2-322%*X=13.2X=60
原式左侧=3*3^x+18/(3^x)>29;令t=3^x(由指数性质知t>0),则3t+18/t>29,整理有3t^2-29t+18>0,即(3t-2)(t-9)>0,则知t的取值范围为0
原式=(x-1)²/2(x²-9)÷[-3(x-1)/4x(x-3)]=(x-1)²/2(x+3)(x-3)×[-4x(x-3)/3(x-1)]=-2x(x-1)/3(x
1、（x+3）（x-6）＜0-3＜x＜62、x²+x-2=2x²-3x-22x²-x²-3x-x=0x²-4x=0x（x-4）=0x=0或者4再问：-
集合A={x/x^2+3x-18>0}={x|x>3或x
x(x-1)=18x-x=18x-x+1/4=18+1/4(x-1/2)=73/4x=1/2±√73/2
1/[x(x+3)]+1/[(x+3)(x+6)]+.+1/[(x+15)(x+18)]=1/3[1/x-1/(x+3)]+[1/(x+3)-1/(x+6)]+.+[1/(x+15)-1/(x+18)
1/x(x+3)+1/(x+3)(x+6)+1/(x+6)(x+9)=[1/x-1/(x+3)+1/(x+3)-1/(x+6)+1(x+6)-1/(x+9)]/3=[1/x-1/(x+9)]/3=3/
3x+1+54-x>292x>29-552x>-26x>-13再问：哪有这么简单啊！x+1和-x都是指数再答：哦3^(x+1)+18*3^(-x)>293*3^x+18/3^x>29设3^x=t显然t
1/√x(√x+2)=1/√x-1/(√x+2)=(√x+2-√x)/√x(√x+2)所以,1/√x(√x+2)+1/(√x+2)(√x+4)+1/(√x+4)(√x+6)+.+1/(√x+18)(√
【不好意思,题目太难让我想了很久】储备知识：x^n-y^n=(x-y)【x^(n-1)+x^(n-2)y+x^(n-3)y²+……+x²y^(n-3)+xy^(n-2)+y^(n-
再问：三道方程再问：x-2/5x=1/10再问：2/3+1/3x=2再问：3x-5X1/3=7/12
A={x|x6}B={x|k=