a: |2x+1|=1
=>x=0(nhận) hoặc x=-1(loại)
KHi x=0 thì B=-2/1=-2
b: \(A=\dfrac{3x-6+4x^2+12x+51-4x^2}{\left(x-2\right)\left(x+3\right)}\)
=\(\dfrac{15x+45}{\left(x-2\right)\left(x+3\right)}=\dfrac{15}{x-2}\)
c: A*B>0
=>\(\dfrac{15}{x-2}\cdot\dfrac{x-2}{x+1}>0\)
=>15/(x+1)>0
=>x+1>0
=>x>-1


