(x²-1分之x 1-1-x分之1)除以x²-x分之x 2
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5x²+x-5=0两根x1,x2,由韦达定理得x1+x2=-1/5x1x2=-5/5=-1x1²+x2²=(x1+x2)²-2x1x2=(-1/5)²
X1+X2=-B/A=2X1*X2=C/A=1/2求得X1=1+根号2或者X1=1-根号2从而求出X2的值X1/X2+X2/X1=(X1*X1+X2*X2)/(X1X2)=6
原式=(-8)*(-81/20)*5/4*1/10=(-8)*5/4*(-81/20)*1/10=(-10)*1/10*(-81/20)=81/20
利用x1+X2=-B/A,x1x2=C/A(1)1/x1+1/x2=(x1+x2)/x1x2=-(-6/2)/(3/2)=-2(2)在菱形ABCD中边长是5,所以有OA^2+OB^2=5^2=25OA
兄弟,真的很简单,但是没有时间给你做你看下韦达定理,全部是基本应用,及两根之和、两根之积的关系,一下就出了.比如第一题,直接通分,第一空-5,第二个-3,第三个是(x1-x2)²=(x1+x
3x的平方+6x-1=0,韦达定理得:X1+X2=-b/a=-2,X1X2=c/a=-1/31/X1+1/X2=(X1+X2)/X1X2=-2/(-1/3)=63x的平方+6x-1=0
a=5,b=-7,c=-3所以x1+x2=7/5x1x2=-3/5所以x1²+x2²=(x1+x2)²-2x1x2=49/25+6/5=79/251/x1+1/x2=(x
(x-3)分之x-(x^2-3x)分之(x+6)+x分之1等于几?=x²/x(x-3)-(x+6)/x(x-3)+(x-3)/x(x-3)=(x²-x-6+x-3)/x(x-3)=
交你方法吧,不然遇到同样问题还是不会,以第一题为例通分,通过分子分母乘以相同数字的办法,将分母搞成一致30分之6x-30分之5x=30分之1去分母,两边同时乘以分母6x-5x=1x=1自己试作做其他的
2x平方-5x-1=0X平方-5/2X-1/2=0X平方-5/2X=1/2X平方-5/2X+5/4的平方=1/2+5/4的平方(X-5/4)平方=33/16X-5/4=正负根号33/4X=正负根号33
x/4+0.75x=1/82x+0.75=12x=0.25x=0.1254(x+0.2)=1.24x=1.2-0.84x=0.4x=0.15x-1/3=2/315x-1=215x=3x=0.2可以重新
x+2/x=c+2/c~x1=c,x2=2/c;x+2/(x-1)=a+2/(a-1);(x-1)+2/(x-1)=(a-1)+2/(a-1);x1-1=a-1;x2-1=2/(a-1);x1=a;x
x²/(x-1)+x/(1-x)=x²/(x-1)-x/-(1-x)=x²/(x-1)-x/(x-1)=x²-x/(x-1)=x(x-1)/(x-1)=x
(x²-1)/x=3/2x²-1-3/2x=02x²-3x-2=0十字相乘x=-1/2或者x=2
2√2-2或-2√2-2
x1+x2=-3/2x1x2=-21/x1+1/x2=(x1+x2)/x1x2=(-3/2)/(-2)=3/4x1²+x2²=(x1+x2)²-2x1x2=(-3/2)&
X1+X2=-6/2=-3X1*X2=-3/21/X1+1/X2=(X1+X2)/(X1X2)=-3/(-3/2)=2
x1+x2=4x1x2=-1(x1+x2)^2/(1/x1+1/x2)=(x1+x2)^2*x1x2/(x1+x2)=x1x2*(x1+x2)=-4