4)A;5)B
Tự luận:
Bài 1:
a)3/2x+6 - x-6/2x²+6x=3x-x+6/2x²+6x
=1/x
b)x²-36/2x+10 . 3/6-x=-(6-x)(6+x)3/(2x+10)(6-x)
=3x-9/2x+10
c)(1/x²+x - 2/x+1):(1/x +x-2)=-1/x+1 : x²-2x+1/x
=-x/(x+1)(x-1)²
Bài2:a)x²+3x+3y+xy=x(x+3)+y(x+3)
=(x+3)(x+y)
Bài 3:
a)2x+10=5(x+4)+7
2x+10-5x-20+7=0
-3x=3
x=-1