已知a 2x的平方 3x 2

X1,X2是方程2x的平方+3x-4=0的两个实数根x1+x2=-3/2x1x2=-2x1^2+2x1x2+x^2=9/4x1^2-2x1x2+x^2=9/4-4x1x2(x1-x2)^2=41/4x

由根与系数的关系可得：x1+x2=-a2，①y1+y2=-5a，②①-②得：x1-y1+x2-y2=-a2+5a．又∵x1-yl=x2-y2=2，∴a2-5a+4=0解得a=1或4．∵方程y2+5ay

x1,x2是方程x平方+6x+3=0的两个实数根,可得：x1+x2=-6;x1x2=3所以有：(x2-x1)^2=(x1+x2)^2-4x1x2=36-12=24即：x2-x1=±2√6x2/x1-x

x1,x2是方程x平方+6x+3=0的两个实数根,可得：x1+x2=-6;x1x2=3（韦达定理）所以有：(x2-x1)^2=(x1+x2)^2-4*x1x2=36-12=24即：x2-x1=±2√6

“x2/x1=x1/x2的值是什么”这里不清楚,请你对一下题目,我十分愿意帮你解答,再问：x2/x1+x1/x2谢谢再答：x1+x2=-6,x1x2=3所以x2/x1+x1/x2=（x1的平方+x2的

x^2-3x+2=0(x-2)(x-1)=0x=2或x=1当x=2时x^2+1/x^2=2^2+1/2^2=4+1/4=17/4当x=1时x^2+1/x^2=1^2+1/1^2=1+1=2

易知x1+x2=7/3,x1x2=2/3,所以（X1+2）(X2+2)=28/3Ⅰx1^2-x^2Ⅰ=(x1+x^2)^2-2x1x2=49/9-4/3=37/9再问：第二题不对吧？？再答：我一般做的

x²+7x-3=0x1+x2=-7;x1x21=-3x1²+x2²=(x1+x2)²-2x1x2=49+6=55(x1-x2)²=(x1+x2)&su

x1+x2=3x1x2=-2007x1的平方加X2的平方=(x1+x2)^2-2x1x2=9+4014=4023

令x=1,得(1²-1+1)^6=a12+a11+a10+……+a2+a1+a0令x=-1,得(1+1+1)^6=a12-a11+a10-……+a2-a1+a0上面两式相加得：2(a12+a

∵x²+6x+3=0∴x1+x2=-6x1x2=3x1/x2+x2/x1=(x1+x2)²-2x1x2/x1x2=10

∵ax=2，ay=3，∴a2x=（ax）2=4，a3y=（ay）3=27，∴a2x+3y=a2x×a3y=4×27=108．

题目有误已知(3-2x)^5=ao+a1x+a2x^2+a3x^3+a4x^4+a5x^5求ao-a1+a2-a3+a4-a5=?和ao+a2+a4=?的值令x=1(3-2)^5=ao+a1+a2+a

由韦达定理x1+x2=3x1x2=1x1²+x2²=(x1+x2)²-2x1x2=3²-2*1=7

x^2+1/x^2=(x+1/x)^2-2=2

根据韦达定理：x1+x2=－b/ax1*x2=c/a代入：x1+x2=－5/3x1*x2=－2/3即：x1+x2+x1*x2=(－5/3)+(－2/3)=－7/3

3x^2+4x-7=0由韦达到理得：x1+x2=-4/3、x1x2=-7/3.x1^2+x2^2=(x1+x2)^2-2x1x2=16/9+14/3=58/9.1/x1^2+1/x2^2=(x1^2+

(2x^2-x-1)^3=a0+a1x+a2x^2+.+a6x^6（*）1）在（*）中令x=-1,则(2+1-1)^3=a0-a1+a2-a3+a4-a5+a6,即a0-a1+a2-a3+a4-a5+

1、∵f(x)=x2-ln(x+1/2)∴f′(x)=2x-1/(x+1/2)令f′(x)=0得x=-1（舍去）x=1/2且x0,∴单调递减区间是[0,1/2)单调递增区间是[1/2,1]∵f(0)=

韦达定理：一元二次方程aX^2+bX+C=0﹙a≠0﹚中,两根X1,X2有如下关系：X1+X2=-b/a,X1·X2=c/a.3x^2-2x-2=0a=3,b=-2,c=-2,-b/a=2/3,c/a