( x^2+3 x)^2- 2(x^2+3x)-8
(x^2+4)^2-16x^2
x^3-8
x^2-6x+8y+y^2+25=0 求根号2 x-3y
100^2 -99^2 +98^2 -97^2 + ......+2^2 -1^2
( x^2+3 x)^2- 2(x^2+3x)-8
(x^2+4)^2-16x^2
x^3-8
x^2-6x+8y+y^2+25=0 求根号2 x-3y
100^2 -99^2 +98^2 -97^2 + ......+2^2 -1^2
1.原式=(x²+3x-4)(x²+3x+2)=(x+4)(x-1)(x+1)(x+2)
2.=(x²+4-4x²)(x²+4+4x²)=(4-3x²)(4+5x²)
3.=(x-2)(x²+2x+4)
4.=(x-3)²+(y+4)²=0,所以,x=3,y=-4,求出来是3根号2
5.=(100+99)(100-99)+(98+97)(98-97)+……+(2+1)(2-1)=199+195+191+……+3=(3+199)*50/2=5050
(1)
=(x^2+3 x-1)^2-3^2
=(x^2+3 x+2)(x^2+3 x-4)
=(x+1)(x+3)(x+4)(x-1)
(2)
=(x^2+4-4x)(x^2+4+4x)
=(x-2)^2(x+2)^2
(3)
=(x-2)(x^2+2x+4)
(4)
(x-3)^2+(y+4)^2=0
x=3,y=-4
x-3y=3+12=15
(5)
=199+195+191+187+...+11+7+1
=(199+1)*50/2
=5000