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3(x一4)二5(x十30)

3(x一4)=5(x十30) 3x-12=5x+150 5x-3x=-12-150 2x=-162 x=(-162)÷2 x=-81

填减号

(1)去括号得:8x+12=8-8x-5x+10,移项,合并同类项得:21x=6,系数化1得:x=27;(2)整理可得:10x?103-10x+205=1.2去分母得:50x-50-30x-60=18,解得:x=6.4.

X~N(3,4),则[(x-3)/2]~N(0,1),所以P(2<X≤5)=P(-0.5<[(X-3)/2]≤1)=1-P(x≤-0.5)-P(X>1)=1-0.3085-0.1587=0.5328,P(-4<X≤10)=P(-3.5<[(X-3)/2]≤3.5)≈1,P(|X|>2)=P(X>2) P(X<-2)=P(X>-0.5) P(X<-2.5)=0.6915 0.0062=0.6977,P(X>3)...

这道题要求计算能力很强 3/x+1/(x-1)+4/(x-2)+4/(x-3)+1/(x-4)+3/(x-5)=0 [3/x+3/(x-5)]+[1/(x-1)+1/(x-4)]+[4/(x-2)+4/(x-3)]=0 (6x-15)/(x^2-5x)+(2x-5)/(x^2-5x+4)+(8x-20)/(x^2-5x+6)=0 (2x-5)[3/(x^2-5x)+1/(x^2-5x+4)+4/(x^2-5x+6)]=0 所...

这是高几的题

(1)当x最大时,x-2=10,解得x=12;当x最小时,5-x=10,解得:x=-5;(2)当15(2+3+4+5+x)=4时,解得:x=6;当15(2+3+4+5+x)=3时,解得:x=1;当15(2+3+4+5+x)=x时,解得:x=3.5;

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