已知A-B=3x²-2x-1,B-C=4-2x²,则C-A=( ) 2.已知m,x,y满足(x-5)²+5×m的绝对值=0第二个条件:-2a²b的y+1次方与3a²b³是同类项,求5m²x+9x²y的值第三题已知xy分之x+y=3求-x+2xy-y
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![已知A-B=3x²-2x-1,B-C=4-2x²,则C-A=( ) 2.已知m,x,y满足(x-5)²+5×m的绝对值=0第二个条件:-2a²b的y+1次方与3a²b³是同类项,求5m²x+9x²y的值第三题已知xy分之x+y=3求-x+2xy-y](/uploads/image/z/1997399-47-9.jpg?t=%E5%B7%B2%E7%9F%A5A-B%3D3x%26%23178%3B-2x-1%2CB-C%3D4-2x%26%23178%3B%2C%E5%88%99C-A%3D%EF%BC%88%E3%80%80%EF%BC%89+2%EF%BC%8E%E5%B7%B2%E7%9F%A5m%2Cx%2Cy%E6%BB%A1%E8%B6%B3%EF%BC%88x-5%EF%BC%89%26%23178%3B%2B5%C3%97m%E7%9A%84%E7%BB%9D%E5%AF%B9%E5%80%BC%3D0%E7%AC%AC%E4%BA%8C%E4%B8%AA%E6%9D%A1%E4%BB%B6%EF%BC%9A-2a%26%23178%3Bb%E7%9A%84y%2B1%E6%AC%A1%E6%96%B9%E4%B8%8E3a%26%23178%3Bb%26%23179%3B%E6%98%AF%E5%90%8C%E7%B1%BB%E9%A1%B9%2C%E6%B1%825m%26%23178%3Bx%2B9x%26%23178%3By%E7%9A%84%E5%80%BC%E7%AC%AC%E4%B8%89%E9%A2%98%E5%B7%B2%E7%9F%A5xy%E5%88%86%E4%B9%8Bx%2By%3D3%E6%B1%82-x%2B2xy-y)
已知A-B=3x²-2x-1,B-C=4-2x²,则C-A=( ) 2.已知m,x,y满足(x-5)²+5×m的绝对值=0第二个条件:-2a²b的y+1次方与3a²b³是同类项,求5m²x+9x²y的值第三题已知xy分之x+y=3求-x+2xy-y
已知A-B=3x²-2x-1,B-C=4-2x²,则C-A=( ) 2.已知m,x,y满足(x-5)²+5×m的绝对值=0
第二个条件:-2a²b的y+1次方与3a²b³是同类项,求5m²x+9x²y的值
第三题已知xy分之x+y=3求-x+2xy-y分之2x-3xy+2y
已知A-B=3x²-2x-1,B-C=4-2x²,则C-A=( ) 2.已知m,x,y满足(x-5)²+5×m的绝对值=0第二个条件:-2a²b的y+1次方与3a²b³是同类项,求5m²x+9x²y的值第三题已知xy分之x+y=3求-x+2xy-y
1解,先将A-B和B-C相加,得A-C=X,再添负号(-),所以最终结果得-X(2)+2X-3.注:X(2)表示X的平方.
因为是同类项,所以指数项y+1=3,y=2,又因为绝对值为零,所以X=5,M=0.所以最后的值为450
由已知得,x+y=3xy,再所求问题中的分子变形为2(x+y)-3xy,分母为-(x+y)+2xy,在将之前的带进去替换得,-3
x=5
c-a=18