Question

tìm m để pt có nghiệm (m là tham số, m\(\in\)R)

\(a,mx-x-m+2=0\)

\(b,m^2\left(x-2\right)+m\left(x+3\right)=2\left(3x-1\right)\)

\(c,m^2x+3mx-m^2+9=0\)

\(d,m^2x-m^2-4=4m\left(x-1\right)\)

Answer 1

a/\(\Leftrightarrow m\left(x-1\right)-\left(x-1\right)=-1\Leftrightarrow\left(m-1\right)\left(x-1\right)=-1\Rightarrow m-1\ne0\Leftrightarrow x\ne1\)

Answer 2

d/\(\Leftrightarrow m^2x-m^2-4-4mx+4m=0\Leftrightarrow m^2\left(x-1\right)-4m\left(x-1\right)=4\Leftrightarrow\left(x-1\right)m\left(m-4\right)=4\Rightarrow\left[{}\begin{matrix}m\ne0\\m\ne4\end{matrix}\right.\)

Answer 3

c/\(\Leftrightarrow mx\left(m+3\right)-\left(m+3\right)\left(m-3\right)=0\Leftrightarrow\left(mx-m+3\right)\left(m+3\right)=0\Rightarrow m\ne-3\)