Question
Solve the following quadratic equation by factorization.
7m2 = 21m
7m2 = 21m
✓
Answer
$\begin{array}{l}
7 m ^2-21 m =0 \\
\Rightarrow 7 m ( m -3)=0 \\
\Rightarrow 7 m =0 \text { or } m -3=0 \\
\Rightarrow m =0 \text { or } m =3
\end{array}$
Hence, $m =0$ or $m =3$ are roots of the equation.
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