2.若﹣4x²y+x²y的b次方=﹣3x²y,则a+b=?1.若多项式a²+2kab与b²-6ab的和不含ab项,则k等于多少?
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![2.若﹣4x²y+x²y的b次方=﹣3x²y,则a+b=?1.若多项式a²+2kab与b²-6ab的和不含ab项,则k等于多少?](/uploads/image/z/575879-23-9.jpg?t=2.%E8%8B%A5%EF%B9%A34x%26%23178%3By%2Bx%26%23178%3By%E7%9A%84b%E6%AC%A1%E6%96%B9%3D%EF%B9%A33x%26%23178%3By%2C%E5%88%99a%2Bb%3D%3F1.%E8%8B%A5%E5%A4%9A%E9%A1%B9%E5%BC%8Fa%26%23178%3B%2B2kab%E4%B8%8Eb%26%23178%3B-6ab%E7%9A%84%E5%92%8C%E4%B8%8D%E5%90%ABab%E9%A1%B9%2C%E5%88%99k%E7%AD%89%E4%BA%8E%E5%A4%9A%E5%B0%91%3F)
2.若﹣4x²y+x²y的b次方=﹣3x²y,则a+b=?1.若多项式a²+2kab与b²-6ab的和不含ab项,则k等于多少?
2.若﹣4x²y+x²y的b次方=﹣3x²y,则a+b=?
1.若多项式a²+2kab与b²-6ab的和不含ab项,则k等于多少?
2.若﹣4x²y+x²y的b次方=﹣3x²y,则a+b=?1.若多项式a²+2kab与b²-6ab的和不含ab项,则k等于多少?
a²+2kab+b²-6ab=a²+(2k-6)ab+b²
∵结果不含ab项
∴2k-6=0
即k=3
﹣4x²y+x²y的b次方=-3x²y
∴b=1
先把两个多项式加和得a^2+b^2+(2k-6)ab 因为不含ab项,所以2k-6=0,所以k=3