3x的平方-9x加25=0-搜答案-搜搜考试网

x^2-3x+1=0即x^2+1=3xx+1/x=(x^2+1)/x=3x/x=3答案是3

x²+3x-1=0x²=1-3xx²+3x=1x的立方加5乘以x的平方加5x加18=x³+5x²+5x+18=x(1-3x)+5(1-3x)+5x+1

把25拆成16+9(x²-8x+16)+(y²+6y+9)=0(x-4)²+(y+3)²=0平方大于等于0,相加等于0若有一个大于0,则另一个小于0,不成立.所

3x^2-7x+3=0等式两边同除x得3x-7+3/x=0即x+1/x=7/33x^2-7x+3=0（1）等式两边同除x^2得3-7/x+3/x^2=0（2）（1）,（2）两式相加得3x^2+3/x^

x平方加3x加1等于0两边同除以xx+3+1/x=0x+1/x=-3两边平方x²+2+1/x²=9所以x²+1/x²=7希望能帮到你,祝学习进步O(∩_∩)O

x^2-3x+1=0x+1/x=(x^2+1)/x=(x^2-3x+1+3x)/x=(0+3x)/x=3x^2+1/x^2=(x+1/x)^2-2=3^2-2=7

x平方减3x加1=0,x^2+1=3xx平方除以（x四次方加x平方加1）=x^2/(X^4+X^2+1)=X^2/{(X^2+1)^2-X^2}=X^2/{(3X)^2-X^2}=1/8

∵x的平方加3x-1=0∴X+3-1／X=0∴X-1／X=-3∴（X-1／X）²=9∴X²-2+1／X²=9∴X²+1／X²=11

题意是这样的吧：求(x²+9x)/(x²+3x)+(x²-9)/(x²+6x+9)原式=(x²+9x)/(x²+3x)+(x+3)(x-3)

【负X】的平方乘X加X的6次方除【负X】的3次方加X的平方乘【负X的平方】加1,=x²·x+x的6次幂÷(-x³)-x的4次幂+1=x³-x³-x的4次幂+1=

x^2+2xy+y^2=25===>(x+y)^2=5^2===>x+y=±5(x-y)^2-3x+3y+2=0===>(x-y)^2-3(x-y)+2=0===>[(x-y)-1]*[(x-y)-2

2x^2-6x+3=02x-6+3/x=02x+3/x=6平方(2x+3/x)^2=364x^2+9/x^2+12=364x^2+9/x^2=24

x平方+3x+1=0x平方+3x+1.5的平方=1.25（x+1.5)平方=1.25x+1.5=±√1.25=±√5/2x=-1.5±√5/2再问：那个1.5是怎么来的？？

(x-3)²+4x(x-3)=0(x-3)[(x-3)+4x]=0(x-3)(5x-3)=0x1=3,x2=3/59(x-2)²=4(x+1)²3(x-2)=2(x+1)

x²+5x+7=3x+11x²+2x+1=5（x+1）²=5x=根号5-1或x=-根号5-1

原式=x(x-9)/x(x+3)-(x+3)(x-3)/(x-3)²=(x-9)/(x+3)-(x+3)/(x-3)=(x²-12x+27-x²-6x-9)/(x+3)(

-x^2+2x+3=0x^2-2x-3=0(x-3)(x+1)=0x=3或x=-1

似乎是x1=-1,x2=-9

x^2-3x+1=0x-3+1/x=0x+1/x=3x^3+1/x^3=(x+1/x)(x^2-1+1/x^2)=3(x^2-1+1/x^2)=3(x^2+2+1/x^2-3)=3[(x+1/x)^2