悬赏100【要(完全平方公式)解题的过程】【1】(x-1/2)²【2】(-4y-1/4)²【3】(x+y-z)²【4】(x-y)²(x+y)²(x²+y²)²【5】已知x²-4x-1=0,①求x²+1/x²
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/23 12:08:46
![悬赏100【要(完全平方公式)解题的过程】【1】(x-1/2)²【2】(-4y-1/4)²【3】(x+y-z)²【4】(x-y)²(x+y)²(x²+y²)²【5】已知x²-4x-1=0,①求x²+1/x²](/uploads/image/z/5473948-4-8.jpg?t=%E6%82%AC%E8%B5%8F100%E3%80%90%E8%A6%81%EF%BC%88%E5%AE%8C%E5%85%A8%E5%B9%B3%E6%96%B9%E5%85%AC%E5%BC%8F%EF%BC%89%E8%A7%A3%E9%A2%98%E7%9A%84%E8%BF%87%E7%A8%8B%E3%80%91%E3%80%901%E3%80%91%EF%BC%88x-1%2F2%EF%BC%89%26%23178%3B%E3%80%902%E3%80%91%EF%BC%88-4y-1%2F4%EF%BC%89%26%23178%3B%E3%80%903%E3%80%91%EF%BC%88x%2By-z%EF%BC%89%26%23178%3B%E3%80%904%E3%80%91%EF%BC%88x-y%EF%BC%89%26%23178%3B%EF%BC%88x%2By%EF%BC%89%26%23178%3B%EF%BC%88x%26%23178%3B%EF%BC%8By%26%23178%3B%EF%BC%89%26%23178%3B%E3%80%905%E3%80%91%E5%B7%B2%E7%9F%A5x%26%23178%3B-4x-1%3D0%2C%E2%91%A0%E6%B1%82x%26%23178%3B%EF%BC%8B1%2Fx%26%23178%3B)
悬赏100【要(完全平方公式)解题的过程】【1】(x-1/2)²【2】(-4y-1/4)²【3】(x+y-z)²【4】(x-y)²(x+y)²(x²+y²)²【5】已知x²-4x-1=0,①求x²+1/x²
悬赏100【要(完全平方公式)解题的过程】
【1】(x-1/2)²
【2】(-4y-1/4)²
【3】(x+y-z)²
【4】(x-y)²(x+y)²(x²+y²)²
【5】已知x²-4x-1=0,①求x²+1/x²的值.②求x的四次方+1/x的四次方的值.
【6】已知x²+y²+6x+8y+25=0,求x²-y²的值.
【7】先化简,再求值:(3x+2)(3x-2)-5x(x-1)-(2x-1)²,其中x=-1/3
悬赏100【要(完全平方公式)解题的过程】【1】(x-1/2)²【2】(-4y-1/4)²【3】(x+y-z)²【4】(x-y)²(x+y)²(x²+y²)²【5】已知x²-4x-1=0,①求x²+1/x²
[1] (x--1/2)^2=x^2--x+1/4.
[2] (--4y--1/4)^2=16y^2+2y+1/16.
[3] (x+y--z)^2=x^2+y^2+z^2+2xy--2yz--2xz.
[4] (x--y)^2(x+y)^2(x^2+y^2)^2
=(x^2--y^2)^2(x^2+y^2)^2
=(x^4--y^4)^2
=x^8--2x^4y^4+y^8.
[5] 因为 x^2--4x--1=0
所以 x--4--1/x=0
x--1/x=4
x^2--2+1/x^2=16
x^2+1/x^2=18.
x^4+2+1/x^4=324
x^4+1/x^4=322.
[6] 因为 x^2+y^2+6x+8y+25=0
所以 (x+3)^2+(y+4)^2=0
x=--3,y=--4,
所以 x^2--y^2=9--16=--7.
[7] (3x+2)(3x--2)--5x(x--1)--(2x--1)^2
=9x^2--4--5x^2+5--4x^2+4x--1
=4x
当x=1/3时,原式的值=4x(1/3)=4/3.
收起
1 =x²-2*1/2*x+(1/2)²=x²-x+1/4
2 =16y²-2*(-4y)*(1/4)+(1/4)²=16y²+2y+1/16
3 =x²+2*x*(y-z)+(y-z)²=x²+2xy-2xz+y²-2yz+z²
4 =((x-y)(x+y))&...
全部展开
1 =x²-2*1/2*x+(1/2)²=x²-x+1/4
2 =16y²-2*(-4y)*(1/4)+(1/4)²=16y²+2y+1/16
3 =x²+2*x*(y-z)+(y-z)²=x²+2xy-2xz+y²-2yz+z²
4 =((x-y)(x+y))²(x²+y²)²=(x²-y²)²(x²+y²)²=((x²-y²)(x²+y²))²=x^4-y^4
收起
前面几题是要化简的吗