化简:(1):4m-7n-2(m-2n).(2):-(x²-2xy-y²)+95x²-2x
1、4m-7n-2(m-2n) 2、-(x²-2xy-y²)+(5x²-2xy-3y
已知M=3x²-2xy+y²,N=2x²+xy-3y²,求:(1)M-N; (2
1、(m-n-3)² 2、x³y-4x²y²+3xy³
计算(1)(3m-4n)(3m+4n)-(2m-2n)(2m+n) (2)(x+5y)²-(x-5y)
分解因式 (x+2y)²-x²-2xy -7m(m-n)³+21mn(n-m)²
(1)已知2x+y=5,xy=2,求4x^2-5xy+y^2的值 (2)已知1/m+1/n=7/m+n,求n/m+m/n
因式分解m²+2m(m-n)+(m-n)²,16-8(x-y)+(x-y)²
已知多项式2x2+xy-3y2-x-4y-1=(2x+3y+m)(x-y+n),求m、n的值.
M=3x²-2xy+y² N=2x²+xy-3y² 求M-N M+N
已知:x,y为实数,M=x²+y²,N=2xy,则M,N的大小关系是()
(1)(2x+y)²-(x+2y)² (2)(m+n)²-4m(m+n)+4m ²
计算:①2m²-m(2m-5n)-n(5m-n)②(3x-y)²-(3x+y)²-2xy③