魔兽世界的感人故事:初二数学题
来源:百度文库 编辑:神马品牌网 时间:2024/04/29 14:10:50
1原式=(X^2-4)^2
=(X+2)^2(X-2)^2
2原式=(X^2+6X+9)-9Y^2
=(X+3)^2-9Y^2
=(X+3Y+3)(X-3Y+3)
3原式=(X^2+6X+9)-9(Y^2+2Y+1)
=(X+3)^2-9(Y+1)^2
=(X+3Y+6)(X-3Y)
4原式=4x^2+16xy+16y^2-25x^2+50xy-25y^2
=-21x^2+66xy_9y^2
=-3(7x^2-22xy+3y^2)
=-3(7x-y)(x-3y)
5. 5(X-Y)-20(X-Y)+20
=20-15(x-y)
你这第5题有毛病吧
原式=(X^2-4)^2
=(X+2)^2(X-2)^2
2原式=(X^2+6X+9)-9Y^2
=(X+3)^2-9Y^2
=(X+3Y+3)(X-3Y+3)
3原式=(X^2+6X+9)-9(Y^2+2Y+1)
=(X+3)^2-9(Y+1)^2
=(X+3Y+6)(X-3Y)
4原式=4x^2+16xy+16y^2-25x^2+50xy-25y^2
=-21x^2+66xy_9y^2
=-3(7x^2-22xy+3y^2)
=-3(7x-y)(x-3y)
5. 5(X-Y)-20(X-Y)+20
=20-15(x-y)
真垃圾!
1原式=(X^2-4)^2
=(X+2)^2(X-2)^2
2原式=(X^2+6X+9)-9Y^2
=(X+3)^2-9Y^2
=(X+3Y+3)(X-3Y+3)
3原式=(X^2+6X+9)-9(Y^2+2Y+1)
=(X+3)^2-9(Y+1)^2
=(X+3Y+6)(X-3Y)
4原式=4x^2+16xy+16y^2-25x^2+50xy-25y^2
=-21x^2+66xy_9y^2
=-3(7x^2-22xy+3y^2)
=-3(7x-y)(x-3y)
5. 5(X-Y)-20(X-Y)+20
=20-15(x-y)
真麻烦!
5题是:5(4-3x+3y)吧.
哎,现在的小朋友的作弊手段可真多啊
3原式=(X^2+6X+9)-9(Y^2+2Y+1)
=(X+3)^2-9(Y+1)^2
=(X+3Y+6)(X-3Y)
2原式=(X^2+6X+9)-9Y^2
=(X+3)^2-9Y^2
=(X+3Y+3)(X-3Y+3)
1原式=(X^2-4)^2
=(X+2)^2(X-2)^2
4原式=4x^2+16xy+16y^2-25x^2+50xy-25y^2
=-21x^2+66xy_9y^2
=-3(7x^2-22xy+3y^2)
=-3(7x-y)(x-3y)
5原式=5(X-Y)-20(X-Y)+20
=20-15(x-y)
=5[4-3(x-y)]