x平方加2x减15等于0
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/06 04:08:40
x³+2x²-5x+2=0x³-x²+3x²-5x+2=0x²﹙x-1﹚+﹙x-1﹚﹙3x-2﹚=0﹙x-1﹚﹙x²+3x-2﹚=
这样的题以后就别问了令t=x平方加xt(t-2)=24t^2-2t-24=0(t-6)(t+4)=0t1=6.t2=-4x^2+x=6或者x^2+x=-4(无解△<0)(x+3)(x-2)=0x1=-
注:下面^2符号表示平方,1/x表示x分之一x-1/x=2∴(x-1/x)^2=x^2-2+1/x^2=4∴x^2+1/x^2=6同理啊:(x^2+1/x^2)^2=x^4+2+x^4=36x^4+2
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
解题思路:利用一元二次方程根的判别式求解。解题过程:解:∵x2-2x+4=0∴△=(-2)2-4×1×4=4-16=-12<0∴此方程无解最终
x^2+2x=3x^4+7x^3+8x^2-13x+15=x^4+2x^3+5x^3+8x^2-13x+15=x^2(x^2+2x)+5x^3+8x^2-13x+15=3x^2+5x^3+8x^2-1
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
X^4-15X^2+10X+24=0(X^4-10X^2+24)-5X(X-2)=0(X-2)(X+2)(X^2-6)-5X(X-2)=0(X-2)(X^3+2X^2-11X-12)=0(X-2)(X
再问:�dz���л��
2x^2-3x+1=0(2x-1)(x-1)=02x-1=0x=1/2x-1=0x=1
问题求什么?再问:求x加y的值再答:x^2-2x+1+y^2-6y+9=0(x-1)^2+(y-3)^2=0x=1y=32x+3y=11
(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)
提供一个解法:设方程为(A1X^2+B1X+C1)(A2x^2+B2X+C2)=0展开系数与原方程相等.得到A1A2=1A1C2+B1B2+A2C1=-15B1C2+B2C1=10C1C2=24A1B
2x²-3x+6=0∵a=2,b=-3,c=6b²-4ac=(-3)²-4×2×6=9-48=-39<0∴原方程无实数根.
4x²+3x-2=0△=9+4×2×4=41x=(-3±√41)/8再问:△=9+4×2×4=41这个是哪里来的呀如果这是一道问答题那它有没有实数解,有几个解再答:△=9+4×2×4=41>
x²+2x-2=0x²+2x+1=2+1(x+1)²=3x+1=±√3x=±√3-1x1=√3-1x2=-√3-1