若多项式2x³-8x²+x-1与多项式3x³+2mx²-5x+3相加后不含x的二次项,则m的值为多少?
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![若多项式2x³-8x²+x-1与多项式3x³+2mx²-5x+3相加后不含x的二次项,则m的值为多少?](/uploads/image/z/1163155-67-5.jpg?t=%E8%8B%A5%E5%A4%9A%E9%A1%B9%E5%BC%8F2x%26%23179%3B-8x%26%23178%3B%2Bx-1%E4%B8%8E%E5%A4%9A%E9%A1%B9%E5%BC%8F3x%26%23179%3B%2B2mx%26%23178%3B-5x%2B3%E7%9B%B8%E5%8A%A0%E5%90%8E%E4%B8%8D%E5%90%ABx%E7%9A%84%E4%BA%8C%E6%AC%A1%E9%A1%B9%2C%E5%88%99m%E7%9A%84%E5%80%BC%E4%B8%BA%E5%A4%9A%E5%B0%91%3F)
若多项式2x³-8x²+x-1与多项式3x³+2mx²-5x+3相加后不含x的二次项,则m的值为多少?
若多项式2x³-8x²+x-1与多项式3x³+2mx²-5x+3相加后不含x的二次项,则m的值为多少?
若多项式2x³-8x²+x-1与多项式3x³+2mx²-5x+3相加后不含x的二次项,则m的值为多少?
2x³-8x²+x-1+3x³+2mx²-5x+3
=5x³+(2m-8)x²-4x+2
∵不含x的二次项
∴2m-8=0
m=4
根据题意,得8=2m,解得m=4