证明x平方 y平方-4x 8y 25总为正
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原式=(x²+y²+2xy)(x²+y²-2xy)/(x+y)²=(x+y)²(x-y)²/(x+y)²=(x-y)
(3x平方-4y平方)+[-(x平方-2xy-y平方)]-[(3x平方-2xy-y平方)]=3x²-4y²-x²+2xy+y²-3x²+2xy+y
∵x的平方+y的平方-4x-6y+13=0x²-4x+4+y²-9x+9=0(x-2)²+(y-6)²=0x-2=0y-6=0∴x=2y=63x+4y=3*2+
x平方+y平方+2xy分之x平方-4y平方除以x平方+xy分之2y+x=(x-2y)(x+2y)/(x+y)²·x(x+y)/(x+2y)=x(x-2y)/(x+y)
4x^2-9y^2=(2x+3y)(2x-3y)
(z²-x²-y²)-4x²y²=(z²-x²-y²-2xy)(z²-x²-y²+2xy)
一式子减去二式子乘以2的差得x²-2xy-3y²=0(x+y)(x-3y)=0x=-y或x=3y当x=-y时代入一式3y²-y²=8y=±2当x=3y时代入一式
(4x-3y)²-16y²=(4x-3y+4y)(4x-3y-4y)=(4x+y)(4x-7y)x²+2x(y-z)+(z-y)²=x²+2x(y-z
证明:f(x)=x^2+1/x^2定义域x≠0,关于y轴对称f(-x)=(-x)^2+1/(-x)^2=x^2+1/x^2=f(x)所以:f(x)是偶函数,关于y轴对称
(x^2+y^2)^2-4x^2y^2=[(x^2+y^2)+2xy][(x^2+y^2)-2xy]=(x^2+2xy+y^2)(x^2-2xy+y^2)=(x+y)^2(x-y)^2
x^2-4y^2-x+2y=(x+2y)(x-2y)-(x-2y)=(x-2y)(x+2y-1)x^2-2x-b^2-2b=(x+b)(x-b)-2(x+b)=(x+b)(x-b-2)
x的平方乘y的平方-4-2x的平方乘y的平方=-x的平方乘y的平方-4
(x^2+y^2)^2-4x^2y^2=(x^2+y^2+2xy)(x^2+y^2-2xy)=(x+y)^2*(x-y)^2=(x^2-y^2)^2数学佰亊嗵为你解答,希望我的回答为您带来帮助!
用反证法.假设此多项式能够分解成两个一次因式的积.设x^2-xy+y^2+x+y=(x+ay+b)(x+cy+d)x^2-xy+y^2+x+y=(x+ay+b)(x+y+d)=x^2+(b+d)x+(
x平方-y平方=4(x+y)(x-y)=4(x+y)平方*(x-y)平方=4*4=16
x²-y²+5x+3y+4=(x²+4x+4)-(y²-4y+4)+x-y+4=(x+2)²-(y-2)²+x-y+4=(x+y)(x-y+
=(x²+y²)²-(2xy)²=(x²+2xy+y²)(x²-2xy+y²)=(x+y)²(x-y)
根据:a²-b²=(a+b)(a-b)(x²+y²)²-(2xy)²假设:(x²+y²)²=a²,(
x的平方-x-4y的平方+2y=(x-2y)(x+2y)-(x-2y)=(x-2y)(x+2y-1)
x平方-4y平方-x-2y=(x+2y)(x-2y)-(x+2y)=(x+2y)(x-2y-1)