a/Thay m=3 đc \(\left(3-2\right)x+3+3=0\)\(\Leftrightarrow x=-9\)
b/\(\Leftrightarrow mx-2x+m-2=0\)
\(\Leftrightarrow m\left(x+1\right)-2\left(x+1\right)=-5\)
\(\Leftrightarrow\left(m-2\right)\left(x+1\right)=-5\). Để PT có nghiệp x duy nhất thì m khác 2
\(\Leftrightarrow x=-\frac{5}{m-2}-1\)\(\Rightarrow x\in Z\Rightarrow m-2\in\left(+-1,+-5\right)\)
\(\Rightarrow m=\left(+-3,1,7\right)\)