已知x的平方减4等于0
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x^2-3x+1=0即x^2+1=3xx+1/x=(x^2+1)/x=3x/x=3答案是3
x²-4x+1=0x²+1=4x两边除以xx+1/x=4x+1/x=4两边平方x²+2+1/x²=16x²+1/x²=14
x²-4x+1=0两边除以x得x-4+1/x=0∴x+1/x=4再问:求x减x分之一的值.再答:你上面不是说求加吗?x²-4x+1=0两边除以x得x-4+1/x=0∴x+1/x=4
再问:姐姐,你多大啦,再答:20再问:哦哦,你家在哪呀,你当我姐姐好不好,?再问:^ω^再问:姐姐,你不说话我就当你默认了哈,!哈哈,姐,!再答:O(∩_∩)O再答:姐姐现在比较忙哦再问:
答:x^2-4x+1=0显然,x不等于0,两边同除以x有:x-4+1/x=0x+1/x=4两边平方得:(x+1/x)^2=16x^2+2+1/x^2=16x^2-2+1/x^2=12所以:(x-1/x
x^2-4x+1=0易证x≠0等式两边除以x得x-4+1/x=0x+1/x=4(x+1/x)^2=16x^2+2+1/x^2=16x^2-2+1/x^2=12(x-1/x)^2=12x-1/x=±2√
x^2+y^2=6y-4x-13x^2+4x+4+y^2-6y+9=0(x+2)^2+(y-3)^2=0x=-2y=3x^2-y^2=(-2)^2-3^2=4-9=-5
x的n次方记作x^n.由方程得1=4x-x^2,x^2+1/x^2=x^2+(4x-x^2)/x^2=x^2+4/x-1=x^2+(16x-4x^2)/x-1=x^2+16-4x-1=x^2-4x+1
x²+x-²=14
X的平方减4X加1等于0x²+1=4x两边同时除以x,得x+1/x=4则(x+1/x)²=4²x²+2+1/x²=16所以x²+1/x
((x-y)(x+y))^2=(x^2-y^2)^2=16,平方差公式
x²+2x-1=0两边同时除以xx+2-1/x=0x-1/x=-2再问:X的平方+1/X的平方再答:(x-1/x)²=4x²+1/x²-2=4x²+1
由x²+2x-1=0两边同除x:x+2-1/x=0,∴x-1/x=-2,(x-1/x)²=(-2)²x²-2+1/x²=4,即x²+1/x&
x加x分之一等于4即x+1/x=4(a)则x平方+2+1/x平方=16两边同减4所以x平方-2+1/x平方=12(x-1/x)平方=12x-1/x=2√3(b)(a)(b)左右相乘得x平方-1/x平方
原式化为y=(x+1/2)^2-25/4x+1/2=5/2或-5/2x=2或-3再问:当x=?时y的值等于24再答:相同原理过程不述x=5或-6
即x²-2x=1所以原式=2x³-4x²+x²-2x-2x+2=2x(x²-2x)+(x²-2x)-2x+2=2x+1-2x+2=3
x^2+4x+y^2-2y+5=0(x^2+4x+4)+(y^2-2y+1)=0(x+2)^2+(y-1)^2=0x=-2,y=1x^2+y^2=(-2)^2+1^2=4+1=5
x²-4x-1=0x²-4x=1所以:(2x-3)²-(x+y)(x-y)-y²=4x²-12x+9-(x²-y²)-y²
x平方-y平方=4(x+y)(x-y)=4(x+y)平方*(x-y)平方=4*4=16