Question

Answer 1

câu 2 thôi nha

 

 

Answer 2

Bài 2:

\(a,ĐK:x\ne\pm\dfrac{3}{2}\\ b,B=\dfrac{4x^2+6x+14x+21}{\left(2x-3\right)\left(2x+3\right)}=\dfrac{\left(2x+3\right)\left(2x+7\right)}{\left(2x-3\right)\left(2x+3\right)}=\dfrac{2x+7}{2x-3}\\ B=\dfrac{5}{2}\Leftrightarrow2\left(2x+7\right)=5\left(2x-3\right)\\ \Leftrightarrow4x+14=10x-15\\ \Leftrightarrow6x=29\Leftrightarrow x=\dfrac{29}{6}\\ c,B=\dfrac{2x+7}{2x-3}=\dfrac{2x-3+10}{2x-3}=1+\dfrac{10}{2x-3}\in Z\\ \Leftrightarrow2x-3\inƯ\left(10\right)=\left\{-10;-5;-2;-1;1;2;5;10\right\}\\ \Leftrightarrow2x\in\left\{-7;-2;1;2;4;5;8;13\right\}\\ \Leftrightarrow x\in\left\{-1;1;2;4\right\}\left(x\in Z\right)\)