1.分解因式:(1)a³(a-b)-8(a-b) (2)(x²+3x)²-2(x²+3x+4) (3)2x²-4xy+2y² (4)x³-4xy² (5)x²-5xy-6y² (6)2x³-162.如果2x²+mxcy+ny²=(x+y)(2x-y),那么m=____,n=____
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1.分解因式:(1)a³(a-b)-8(a-b) (2)(x²+3x)²-2(x²+3x+4) (3)2x²-4xy+2y² (4)x³-4xy² (5)x²-5xy-6y² (6)2x³-162.如果2x²+mxcy+ny²=(x+y)(2x-y),那么m=____,n=____
1.分解因式:(1)a³(a-b)-8(a-b) (2)(x²+3x)²-2(x²+3x+4) (3)2x²-4xy+2y² (4)x³-4xy² (5)x²-5xy-6y² (6)2x³-16
2.如果2x²+mxcy+ny²=(x+y)(2x-y),那么m=____,n=_____
3.计算:(1)x/(x²-1)·x²-x-2/x²-2x (2)(1/2+a/2a+2)÷a²-a/a²-1
1.分解因式:(1)a³(a-b)-8(a-b) (2)(x²+3x)²-2(x²+3x+4) (3)2x²-4xy+2y² (4)x³-4xy² (5)x²-5xy-6y² (6)2x³-162.如果2x²+mxcy+ny²=(x+y)(2x-y),那么m=____,n=____
(1)a³(a-b)-8(a-b)
=(a-b) (a-2)(a²+2a+4)
(2)(x²+3x)²-2(x²+3x+4)
=(x²+3x)²-2(x²+3x)-8
=(x²+3x-4)(x²+3x+2)
=(x+4)(x-1)(x+1)(x+2)
(3)2x²-4xy+2y²
=2(x-y)²
(4)x³-4xy²
=x(x+2y)(x-2y)
(5)x²-5xy-6y²
=(x-6y)(x+y)
(6)2x³-16
=2(x-2)(x²+2x+4)
2.如果2x²+mxcy+ny²=(x+y)(2x-y),那么m=____,n=_____
(x+y)(2x-y)
=2x²+xy-y²
所以
m=1 n=-1
3.计算:(1)x/(x²-1)·x²-x-2/x²-2x
=x/(x+1)(x-1)*(x-2)(x+1)/x(x-2)
=x/(x-1)*1/x
=1/(x-1
(2)(1/2+a/2a+2)÷a²-a/a²-1
=[1/2+a/2(a+1)]÷a(a-1)/(a+1)(a-1)
=[1/2+a/2(a+1)]÷a/(a+1)
=[1/2+a/2(a+1)]*(a+1)/a
=(2a+1)/2(a+1)*(a+1)/a
=(2a+1)/a