用完全平方公式解答,明天就开学啦,速度的话追分1.(三分之一x+3y)²= ( )²=四分之一y²-y+12.(a+b-c)²= 3.代数式2xy-x²-y²等于4(x+y/2)²-(x-y/2)²等于5.已知x-y=4,xy=12,则x
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![用完全平方公式解答,明天就开学啦,速度的话追分1.(三分之一x+3y)²= ( )²=四分之一y²-y+12.(a+b-c)²= 3.代数式2xy-x²-y²等于4(x+y/2)²-(x-y/2)²等于5.已知x-y=4,xy=12,则x](/uploads/image/z/2598327-63-7.jpg?t=%E7%94%A8%E5%AE%8C%E5%85%A8%E5%B9%B3%E6%96%B9%E5%85%AC%E5%BC%8F%E8%A7%A3%E7%AD%94%2C%E6%98%8E%E5%A4%A9%E5%B0%B1%E5%BC%80%E5%AD%A6%E5%95%A6%2C%E9%80%9F%E5%BA%A6%E7%9A%84%E8%AF%9D%E8%BF%BD%E5%88%861.%EF%BC%88%E4%B8%89%E5%88%86%E4%B9%8B%E4%B8%80x%2B3y%29%26%23178%3B%3D+%EF%BC%88+%EF%BC%89%26%23178%3B%3D%E5%9B%9B%E5%88%86%E4%B9%8B%E4%B8%80y%26%23178%3B-y%2B12.%28a%2Bb-c%29%26%23178%3B%3D+3.%E4%BB%A3%E6%95%B0%E5%BC%8F2xy-x%26%23178%3B-y%26%23178%3B%E7%AD%89%E4%BA%8E4%EF%BC%88x%2By%2F2%29%26%23178%3B-%EF%BC%88x-y%2F2%29%26%23178%3B%E7%AD%89%E4%BA%8E5.%E5%B7%B2%E7%9F%A5x-y%3D4%2Cxy%3D12%2C%E5%88%99x%26%231)
用完全平方公式解答,明天就开学啦,速度的话追分1.(三分之一x+3y)²= ( )²=四分之一y²-y+12.(a+b-c)²= 3.代数式2xy-x²-y²等于4(x+y/2)²-(x-y/2)²等于5.已知x-y=4,xy=12,则x
用完全平方公式解答,明天就开学啦,速度的话追分
1.(三分之一x+3y)²= ( )²=四分之一y²-y+1
2.(a+b-c)²=
3.代数式2xy-x²-y²等于
4(x+y/2)²-(x-y/2)²等于
5.已知x-y=4,xy=12,则x²+y²的值是
6.计算
(1)(3ax+1)²-(ab-1)²
(2)(a-2b+c)(a+2b+c)
(3)(x/2-y)²-1/4(x²+y²)
用平方差公式解答
(1)(x+2y)(x-2y)+(x+1)(x-1) (2) x(x-1)-(x-1/3)(x+1/3)
用完全平方公式解答,明天就开学啦,速度的话追分1.(三分之一x+3y)²= ( )²=四分之一y²-y+12.(a+b-c)²= 3.代数式2xy-x²-y²等于4(x+y/2)²-(x-y/2)²等于5.已知x-y=4,xy=12,则x
1.(三分之一x+3y)²=1/9*x^2+2xy+9y^2;
(1/2*y-1)²=四分之一y²-y+1.
2.(a+b-c)²=a^2+b^2+c^2+2ab-2bc-2ca.
3.2xy-x²-y²=-(x-y)^2.
4.(x+y/2)²-(x-y/2)²=(x^2+xy+y^2/4)-(x^2-xy+y^2/4)=2xy
或者(x+y/2)²-(x-y/2)²=[(x+y/2)+(x-y/2)][(x+y/2)-(x-y/2)]=2x*y=2xy.
5.x²+y²=(x-y)^2+2xy=16+24=40.
6(1)(3ax+1)²-(ab-1)²=9a^2*x^2+6ax+1-a^2*b^2+2ab-1=9a^2*x^2+6ax-a^2*b^2+2ab;
(2)(a-2b+c)(a+2b+c)=[(a+c)+2b][(a+c)-2b]=(a+c)^2-4b^2=a^2+2ac+c^2-4b^2.
(3)(x/2-y)²-1/4(x²+y²)=x^2/4-xy+y^2-x^2/4-y^2/4=3y^2/4-xy.
用平方差公式解答
(1)(x+2y)(x-2y)+(x+1)(x-1)=x^2-4y^2+x^2-1=2x^2-4y^2-1.
(2) x(x-1)-(x-1/3)(x+1/3)=x^2-x-x^2+1/9=1/9-x.
1.(三分之一x+3y)²=1/9 x ² +2xy+9y² ( 1/2y-1 )²=四分之一y²-y+1
2.(a+b-c)²= a²+b²+c²+2ab-2ac-2bc
3.代数式2xy-x²-y²等于--(x-y)²...
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1.(三分之一x+3y)²=1/9 x ² +2xy+9y² ( 1/2y-1 )²=四分之一y²-y+1
2.(a+b-c)²= a²+b²+c²+2ab-2ac-2bc
3.代数式2xy-x²-y²等于--(x-y)²
4(x+y/2)²-(x-y/2)²等于(x+y/2+x-y/2)*(x+y/2-x+y/2)=2x*y
5.已知x-y=4,xy=12,则x²+y²=(x-y)²+2xy=4²+2*12=40
6.计算
(1)(3ax+1)²-(ab-1)²=(3ax+1+ab-1)(3ax+1-ab+1)=9a² x² +6ax-a² b² +2ab
(2)(a-2b+c)(a+2b+c)=[(a+c)-2b]*[(a+c)+2b]=)=(a+c)² -(2b)² =a² +2ac+c² -4b²
(3)(x/2-y)²-1/4(x²+y²)==x² /4-xy+y² -1/4x²-1/4y²=3/4y²-xy
用平方差公式解答
(1)(x+2y)(x-2y)+(x+1)(x-1) =x²-4y² +x²-1= 2 x²-4y²-1
(2) x(x-1)-(x-1/3)(x+1/3)=x²-x+1/9
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