以知xy,x2加2xy加4y2=6
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①x2+2xy-y2不符合完全平方公式的特点,不能用完全平方公式进行因式分解;②-x2-y2+2xy符合完全平方公式的特点,能用完全平方公式进行因式分解;③x2+xy+y2不符合完全平方公式的特点,不
x2-xy=-3①,2xy-y2=-8②,①×2+②×3得:2x2-2xy+6xy-3y2=-6-24=-30,则2x2+4xy-3y2=-30.
∵x2-xy=7,2xy+y2=4,∴原式=(x2-xy)+(2xy+y2)=7+4=11,故答案为:11
A、原式=-6x2-19xy-5y2;B、原式=2x2-9xy-7y2;C、原式=x2-16xy-10y2;D、原式=8x2-13xy-15y2.故选D.
5x2—3xy—4y2—11xy—7x2+2y2=-2x2-2y2-14xy=-2(x2+y2)-14xy=-14+28=14
x+y=7xy=27^2=(x+y)^2=x^2+2xy+y^2=x^2+y^2+2*2x^2+y^2=45(1)y=7-xx(7-x)=2x^2-7x+2=0x=(7+41^(1/2))/2或x=(
再问:你确定吗?再答:我保证再答:亲,那一步不明白可以问再问:你省略了一步吧!再答:能看明白吗再问:no再答: 再答:是不是这部再问:那么第一步是怎么得来的呢?再答:第一步不是你
X2+xy-(xy+y2)=4-12x2+xy-xy-y2=-8x2-y2=-8x2+xy+xy+y2=4+12x2+2xy+y2=16
X2-1-2xy+y2=X2-2XY+Y2-1=(X2-2XY+Y2)-1=(X-Y)2-1=(X-Y-1)(X-Y+1)(x2+4y2)2-16x2y2=(x2+4y2)2-(4XY)2=(X2+4
十字相乘法原式=(2x-3y)(x+y)
原式=(2x²-3xy+4y²)+(x²+2xy-3y²)=(2x²+x²)+(-3xy+2xy)+(4y²-3y²)=
原式=(x2-2xy+y2)-z2=(x-y)2-z2=(x-y+z)(x-y-z).
7x2-3xy-2y2-11xy-5x2+4y2=2x²-14xy+2y²=2(x²+y²)-14xy=2×7-14×(-2)=14+28=42
∵x2+y2=7,xy=-2,∴7x2-3xy-2y2-11xy-5x2+4y2,=(7x2-5x2)+(4y2-2y2)-(3xy+11xy),=2x2+2y2-14xy,=2(x2+y2)-14x
6x2-xy-15y2=(2x+3y)(3x-5y)=0,所以x=-3/2y或x=5/3y
x2y2+3xy+2=(xy)^2+3xy+2=(xy+2)(xy+1)很高兴能帮助您~!
很难,因为不能变成系数为整数甚至分数的因式积.
2x²+xy-3y²+x+4y-1=2×x×x+x×y-3×y×y+x+4×y-1=x×2x+x×y-y×3y+x×1+y×4-1=x×(2x+y+1)-y×(3y+4)-1再问:
x2-2xy+y2-9,=x2-2xy+y2-9,=(x2-2xy+y2)-9,=(x-y)2-32,=(x-y+3)(x-y-3).
因为x²+4y²+x²y²-6xy+1=0(x²-4xy+4y²)+(x²y²-2xy+1)=0(x-2y)²