A=\(\dfrac{2x+7}{x+2}\)
⇔A=\(\dfrac{2x+4+3}{x+2}\)\(\dfrac{3}{x+2}\)
A=\(\dfrac{2.\left(x+2\right)}{x+2}\)+\(\dfrac{3}{x+2}\)
A=2+\(\dfrac{3}{x+2}\)
Để A nguyên⇒\(\dfrac{3}{x+2}\)nguyên hay (x+2)∈Ư(3)=1,-1,3,-3
Nếu x+2=1 Nếu x+2=-1 Nếu x+2=3 Nếu x+2=-3
⇒x=-1(tm) ⇒x=-3(tm) ⇒x=1(tm) ⇒x=-5(tm)
B=\(\dfrac{7-4x}{2x-1}\)
⇔B=\(\dfrac{5+2-4x}{2x-1}\)
B=\(\dfrac{5}{2x-1}\)-\(\dfrac{-2+4x}{2x-1}\)
B=\(\dfrac{5}{2x-1}-\dfrac{2\left(2x-1\right)}{2x-1}\)
B=\(\dfrac{5}{2x-1}-2\)
B= Để A nguyên⇒\(\dfrac{5}{2x-1}\)nguyên hay (2x-1)∈Ư(2)=1,-1,5,-5
Nếu 2x-1=1 Nếu 2x-1 =-1
⇒x=1(tm) ⇒x=0(tm)
Nếu 2x-1=5 Nếu 2x-1=-5
⇒x=3(tm) ⇒x=-2(tm)
