Đáp án:
a, 2x(x2+xy+3)2x(x2+xy+3)
=2x3+2x2y+6x=2x3+2x2y+6x
b, (5x−3)(2x+y+10)(5x-3)(2x+y+10)
=10x2−6x+5xy−3y+50x−30=10x2-6x+5xy-3y+50x-30
=10x2−(6x−50x)+5xy−30=10x2-(6x-50x)+5xy-30
=10x2+44x+5xy−30=10x2+44x+5xy-30
c, x3y4:x3yx3y4:x3y
=y3=y3
d, (15x3y2+7xy−6y):3xy(15x3y2+7xy-6y):3xy
=5x2y+2,3−2x=5x2y+2,3-2x
e, (x3−3x2+x−3):(x−3)(x3-3x2+x-3):(x-3)
=x2−3x−3x−3x3+x2+3x=x2-3x-3x-3x3+x2+3x
=(x2+x2)−(3x+3x−3x)−3x3=(x2+x2)-(3x+3x-3x)-3x3
=2x2−3x−3x3=2x2-3x-3x3
Bài 1 :
a, x3+2x2y+y2x+2y3x3+2x2y+y2x+2y3
=(x3+2x2y)+(y2x+2y3)=(x3+2x2y)+(y2x+2y3)
=x^2(x+y)+y2(x+y)=x2(x+y)+y2(x+y)
=(x+y)(x^2+y^2)