Question

求一个数学题的解

3.98的平方减2.98乘以3.97 利用因式分解计算，求过程，求方法，急！！！！！！！

Answer 1

3.98的平方-2.98乘以3.97
=3.98的平方-2.98乘以(3.97 +0.01-0.01)
=3.98的平方 - 2.98乘以(3.98 -0.01)
=3.98的平方 -2.98乘以3.98 + 2.98乘以0.01
=3.98乘以(3.98 - 2.98) +0.0298
=3.98乘以1 +0.0298
=4.0098

Answer 2

解：
3.98²-2.98x3.97
=3.98²-(3.98-1)x3.97
=3.98²-3.98x3.97+3.97
=3.98x(3.98-3.97)+3.97
=0.0398+4-0.03
=4.0098

Answer 3

3.98^2-2.98*3.97
=3.98^2-(3.98-1)*3.97
=3.98^2-3.98*3.97+3.97
=3.98(3.98-3.97)+3.97
=3.98*0.01+3.97
=0.0398+3.97
=4.0098

追问

你......是算错了吧？你这个方法是等于4.0198，不过，谢谢！

Answer 4

3.98^2-2.98*3.97
=3.98^2-(4-1.02)(4-0.03)
=3.98^2-3.98x3.97+3.97

=3.98(3.98-3.97)+3.97
=3.98*0.01+3.97
=0.0398+3.97
=4.0098

希望采纳

追问

给你的评价如上，谢谢！

Answer 5

3.98^2 - 2.98*3.97
=3.98^2 - （3.98-1）*(3.98-0.01)
=3.98^2-3.98^2+3.98*0.01+3.98-0.01
=3.97+0.0398
=4.0098

Answer 6

3.98^2 - 2.98*3.97
=3.98^2 - 2.98*(3.98-0.01)
=3.98^2 - 2.98*3.98-2.98*0.01
=3.98*(3.98-2.98) - 2.98*0.01
=3.98*1 - 0.0298
=3.9502

追问

你没变号吧......所以才算错的...不过还是谢谢