(1/2a-3b)²(1/2a+3b)²一.(2x-3y+4)(2x+3y-4)二.若x²+3/4x+2k是完全平方公式,则k=?三.(x-2y+z)²
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/06 20:13:44
![(1/2a-3b)²(1/2a+3b)²一.(2x-3y+4)(2x+3y-4)二.若x²+3/4x+2k是完全平方公式,则k=?三.(x-2y+z)²](/uploads/image/z/7941968-8-8.jpg?t=%EF%BC%881%2F2a-3b%EF%BC%89%26%23178%3B%EF%BC%881%2F2a%2B3b%EF%BC%89%26%23178%3B%E4%B8%80.%282x-3y%2B4%29%282x%2B3y-4%29%E4%BA%8C.%E8%8B%A5x%26%23178%3B%2B3%2F4x%2B2k%E6%98%AF%E5%AE%8C%E5%85%A8%E5%B9%B3%E6%96%B9%E5%85%AC%E5%BC%8F%EF%BC%8C%E5%88%99k%3D%EF%BC%9F%E4%B8%89.%EF%BC%88x-2y%2Bz%EF%BC%89%26%23178%3B)
(1/2a-3b)²(1/2a+3b)²一.(2x-3y+4)(2x+3y-4)二.若x²+3/4x+2k是完全平方公式,则k=?三.(x-2y+z)²
(1/2a-3b)²(1/2a+3b)²
一.(2x-3y+4)(2x+3y-4)
二.若x²+3/4x+2k是完全平方公式,则k=?
三.(x-2y+z)²
(1/2a-3b)²(1/2a+3b)²一.(2x-3y+4)(2x+3y-4)二.若x²+3/4x+2k是完全平方公式,则k=?三.(x-2y+z)²
(1/2a-3b)²(1/2a+3b)²
=[(1/2a-3b)(1/2a+3b)]²
=(1/4a²-9b²)²
=1/16a^4+9/2a²b²+81b^4
(2x-3y+4)(2x+3y-4)
=[2x-(3y-4)][2x+(3y-4)]
=4x²-(3y-4)²
=4x²-(9y²-24y+16)
=4x²-9y²+24y-16
x²+3/4x+2k
=(x²+3/4x+9/64)-9/64+2k
=(x+3/8)²-9/64+2k
∵x²+3/4x+2k是完全平方式
∴-9/64=2k
∴2k=9/64
∴k=9/32
(x-2y+z)²
=[(x-2y)+z]²
=(x-2y)²+2z(x-2y)+z²
=x²-4y+4y²-2xz+4yz+z²
很高兴为您解答,【数学之美】团队为您答题.
请点击下面的【选为满意回答】按钮,
(1/2a-3b)²(1/2a+3b)²
=[(1/2a-3b)(1/2a+3b)]²
=[1/4a²-9b²]²
=1/16a^4-9/2a^2b^2+81b^4
(2x-3y+4)(2x+3y-4)
=[2x-(3y-4)]*[2x+(3y-4)]
=(2x)^2-(3y-4)^2
全部展开
(1/2a-3b)²(1/2a+3b)²
=[(1/2a-3b)(1/2a+3b)]²
=[1/4a²-9b²]²
=1/16a^4-9/2a^2b^2+81b^4
(2x-3y+4)(2x+3y-4)
=[2x-(3y-4)]*[2x+(3y-4)]
=(2x)^2-(3y-4)^2
=4x^2-9y^2+24y-16
二.若x²+3/4x+2k是完全平方公式,则k=?
配方得:x²+3/4x+2k
=(x²+3/4x+9/64)-9/64+2k
=(x+3/8)²-9/64+2k
因为x²+3/4x+2k是完全平方公式,则-9/64+2k=0,k=9/32
三.(x-2y+z)²
=[(x-2y)+z]²
=(x-2y)²+2(x-2y)z+z²
=x²-4xy+4y²+2xz-4yz+z²
收起
a-6b ?对?