有没有数学好点的人,帮我解答一些分解因式.7x3y-21x2y2;3ax2+6axy+3ay2;3(a-b)-21(b-a)2;16-25t2.
2019-04-20
有没有数学好点的人,帮我解答一些分解因式.
7x3y-21x2y2;3ax2+6axy+3ay2;3(a-b)-21(b-a)2;16-25t2.
优质解答
7x^3y-21x^2y^2
=7x^2y(x-3y)
3ax^2+6axy+3ay^2
=3a(x^2+2xy+y^2)
=3a(x+y)^2
3(a-b)-21(b-a)^2
=3(a-b)(1-7a+7b)
16-25t^2
=(4-5t)(t+5t)
7x^3y-21x^2y^2
=7x^2y(x-3y)
3ax^2+6axy+3ay^2
=3a(x^2+2xy+y^2)
=3a(x+y)^2
3(a-b)-21(b-a)^2
=3(a-b)(1-7a+7b)
16-25t^2
=(4-5t)(t+5t)